Variation of Parameters Bernd Schr oder logo1 Bernd Schr oder - PowerPoint PPT Presentation
Overview An Example Double Check Further Discussion Variation of Parameters Bernd Schr oder logo1 Bernd Schr oder Louisiana Tech University, College of Engineering and Science Variation of Parameters Overview An Example Double
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Solution of the homogeneous equation. y ′′ + 4 y ′ + 4 y = 0 λ 2 e λ x + 4 λ e λ x + 4 e λ x = 0 λ 2 + 4 λ + 4 = 0 √ − 4 ± 16 − 16 = = − 2 λ 1 , 2 2 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Solution of the homogeneous equation. y ′′ + 4 y ′ + 4 y = 0 λ 2 e λ x + 4 λ e λ x + 4 e λ x = 0 λ 2 + 4 λ + 4 = 0 √ − 4 ± 16 − 16 = = − 2 λ 1 , 2 2 c 1 e − 2 x + c 2 xe − 2 x = y h logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the Wronskian. e − 2 t � e − 2 t − 2 te − 2 t � − te − 2 t � − 2 e − 2 t � W ( y 1 , y 2 )( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the Wronskian. e − 2 t � e − 2 t − 2 te − 2 t � − te − 2 t � − 2 e − 2 t � W ( y 1 , y 2 )( t ) = e − 4 t − 2 te − 4 t + 2 te − 4 t = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the Wronskian. e − 2 t � e − 2 t − 2 te − 2 t � − te − 2 t � − 2 e − 2 t � W ( y 1 , y 2 )( t ) = e − 4 t − 2 te − 4 t + 2 te − 4 t = e − 4 t = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) sin ( t ) 1 1 � � e − 2 t dt a 2 ( t ) y 1 ( t ) dt = W ( y 1 , y 2 )( t ) e − 4 t 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) sin ( t ) 1 1 � � e − 2 t dt a 2 ( t ) y 1 ( t ) dt = W ( y 1 , y 2 )( t ) e − 4 t 1 � e 2 t sin ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � e 2 t sin ( t ) dt logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 1 2 e 2 t sin ( t ) − 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 1 2 e 2 t sin ( t ) − 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 1 2 e 2 t sin ( t ) − 1 4 e 2 t cos ( t ) − 1 � e 2 t sin ( t ) dt = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 1 2 e 2 t sin ( t ) − 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 1 2 e 2 t sin ( t ) − 1 4 e 2 t cos ( t ) − 1 � e 2 t sin ( t ) dt = 4 5 1 2 e 2 t sin ( t ) − 1 � e 2 t sin ( t ) dt 4 e 2 t cos ( t ) = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 2 e 2 t sin ( t ) − 1 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 1 2 e 2 t sin ( t ) − 1 4 e 2 t cos ( t ) − 1 � e 2 t sin ( t ) dt = 4 5 1 2 e 2 t sin ( t ) − 1 � e 2 t sin ( t ) dt 4 e 2 t cos ( t ) = 4 2 5 e 2 t sin ( t ) − 1 � e 2 t sin ( t ) dt 5 e 2 t cos ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 � te 2 t sin ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 � te 2 t sin ( t ) dt = � 2 � 2 � 5 e 2 t sin ( t ) − 1 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) 5 e 2 t cos ( t ) dt = t − logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 � te 2 t sin ( t ) dt = � 2 � 2 � 5 e 2 t sin ( t ) − 1 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) 5 e 2 t cos ( t ) dt = t − 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � e 2 t cos ( t ) dt logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 1 2 e 2 t cos ( t )+ 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 2 e 2 t cos ( t )+ 1 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 1 2 e 2 t cos ( t )+ 1 4 e 2 t sin ( t ) − 1 � e 2 t cos ( t ) dt = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 1 2 e 2 t cos ( t )+ 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 1 2 e 2 t cos ( t )+ 1 4 e 2 t sin ( t ) − 1 � e 2 t cos ( t ) dt = 4 5 1 2 e 2 t cos ( t )+ 1 � e 2 t cos ( t ) dt 4 e 2 t sin ( t ) = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 1 2 e 2 t cos ( t )+ 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 1 2 e 2 t cos ( t )+ 1 4 e 2 t sin ( t ) − 1 � e 2 t cos ( t ) dt = 4 5 1 2 e 2 t cos ( t )+ 1 � e 2 t cos ( t ) dt 4 e 2 t sin ( t ) = 4 2 5 e 2 t cos ( t )+ 1 � e 2 t cos ( t ) dt 5 e 2 t sin ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 5 te 2 t sin ( t ) − 1 2 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 � 2 � 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) = 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 � 2 � 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) = 5 � 2 � + 1 5 e 2 t cos ( t )+ 1 5 e 2 t sin ( t ) 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 � 2 � 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) = 5 � 2 � + 1 5 e 2 t cos ( t )+ 1 5 e 2 t sin ( t ) 5 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 3 25 e 2 t sin ( t )+ 4 25 e 2 t cos ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x � 2 � 5 e 2 x sin ( x ) − 1 5 e 2 x cos ( x ) + xe − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x � 2 � 5 e 2 x sin ( x ) − 1 5 e 2 x cos ( x ) + xe − 2 x 25 sin ( x ) − 4 3 = 25 cos ( x ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x � 2 � 5 e 2 x sin ( x ) − 1 5 e 2 x cos ( x ) + xe − 2 x 25 sin ( x ) − 4 3 = 25 cos ( x ) y = − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = 1 = y ( 0 ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 1 = 25 + c 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 = 25 − 2 c 1 + c 2 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 = 25 − 2 c 1 + c 2 , 0 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 25 = 55 = 25 − 2 c 1 + c 2 , 0 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 25 = 55 25 = 11 = 25 − 2 c 1 + c 2 , 0 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 25 = 55 25 = 11 = 25 − 2 c 1 + c 2 , 0 5 − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x = y logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � − 16 25 + 12 25 + 4 cos ( x ) 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 � 116 � 25 − 232 25 + 44 5 + 116 25 − 44 e − 2 x + 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 � 116 � � 44 � 25 − 232 25 + 44 5 + 116 25 − 44 5 − 88 5 + 44 e − 2 x + xe − 2 x + 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 � 116 � � 44 � 25 − 232 25 + 44 5 + 116 25 − 44 5 − 88 5 + 44 ? e − 2 x + xe − 2 x + = sin ( x ) 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 √ � 116 � � 44 � 25 − 232 25 + 44 5 + 116 25 − 44 5 − 88 5 + 44 e − 2 x + xe − 2 x + = sin ( x ) 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? − 4 25 + 29 y ( 0 ) = 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? − 4 25 + 29 y ( 0 ) = 25 = 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 y ′ ( 0 ) = 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 y ′ ( 0 ) = 25 = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 √ y ′ ( 0 ) = 25 = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 √ y ′ ( 0 ) = 25 = 0 Alternatively, use a computer to double check the result. logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 √ y ′ ( 0 ) = 25 = 0 Alternatively, use a computer to double check the result. Beyond a certain level of complexity, that really is the way to go. logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Double Checking with a Computer Algebra System logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Double Checking with a Computer Algebra System logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
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