Use substitution: Use substitution. Let u=log(x), then du=x1dx or dx=xdu.
Substitute and integrate: Since x=eu, substitute x and dx in the integral.∫sin(log(x))dx=∫sin(u)eudu
Integration by parts: Use integration by parts. Let v=sin(u) and dw=eudu. Then dv=cos(u)du and w=eu.
Apply integration by parts: Apply the integration by parts formula ∫vdw=vw−∫wdv.∫sin(u)eudu=sin(u)eu−∫eucos(u)du
Use integration by parts again: Use integration by parts again on ∫eucos(u)du. Let v=cos(u) and dw=eudu. Then dv=−sin(u)du and w=eu.
Combine results: Apply the integration by parts formula again.∫eucos(u)du=cos(u)eu−∫eu(−sin(u))du=cos(u)eu+∫eusin(u)du
Solve for integral: Combine the results from Steps 4 and 6.∫sin(u)eudu=sin(u)eu−(cos(u)eu+∫eusin(u)du)=sin(u)eu−cos(u)eu−∫eusin(u)du
Substitute back: Solve for ∫eusin(u)du.∫eusin(u)du+∫eusin(u)du=sin(u)eu−cos(u)eu2∫eusin(u)du=sin(u)eu−cos(u)eu∫eusin(u)du=21(sin(u)eu−cos(u)eu)
Substitute back: Solve for ∫eusin(u)du.∫eusin(u)du+∫eusin(u)du=sin(u)eu−cos(u)eu2∫eusin(u)du=sin(u)eu−cos(u)eu∫eusin(u)du=21(sin(u)eu−cos(u)eu)Substitute back u=log(x).∫sin(log(x))dx=21(sin(log(x))x−cos(log(x))x)+C
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