Recognize functions for integration: Recognize the integral as a product of two functions suitable for integration by parts.Integration by parts formula: ∫udv=uv−∫vduLet u=5x and dv=cos(5x)dx.
Differentiate and integrate: Differentiate u and integrate dv.Differentiating u gives us du=5dx.Integrating dv gives us v=∫cos(5x)dx=51sin(5x).
Apply integration by parts: Apply the integration by parts formula. ∫5xcos(5x)dx=uv−∫vdu= (5x)(51)sin(5x)−∫(51)sin(5x)(5dx)= xsin(5x)−∫sin(5x)dx
Integrate sin(5x): Integrate ∫sin(5x)dx.∫sin(5x)dx=−(51)cos(5x)+C, where C is the constant of integration.
Combine final answer: Combine the results to get the final answer.∫5xcos(5x)dx=xsin(5x)−(−(51)cos(5x))+C=xsin(5x)+(51)cos(5x)+C
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