Choose u and dv: We will use integration by parts to solve the integral of xcos(x)dx. Integration by parts is given by the formula ∫udv=uv−∫vdu, where u and dv are parts of the integrand that we choose. We will let u=x and dv=cos(x)dx.
Find du and v: Differentiate u to find du, and integrate dv to find v. So, du=dx and v=sin(x). We can now apply the integration by parts formula.
Apply integration by parts: Substitute u, v, and du into the integration by parts formula to get ∫xcos(x)dx=xsin(x)−∫sin(x)dx.
Integrate sin(x): Now we need to integrate ∫sin(x)dx, which is a basic integral. The integral of sin(x) with respect to x is −cos(x).
Substitute sin(x) integral: Substitute the integral of sin(x) into the equation from the previous step to get ∫xcos(x)dx=xsin(x)−(−cos(x)).
Simplify the equation: Simplify the equation by distributing the negative sign to get ∫xcos(x)dx=xsin(x)+cos(x)+C, where C is the constant of integration.
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