Identify integral: Identify the integral to be solved.We need to evaluate the integral of the function (1+x2)23xtan−1x with respect to x.
Choose substitution: Choose a substitution.Let u=tan−1x, which implies x=tan(u). Then, we need to find dx in terms of du.
Differentiate u: Differentiate u with respect to x to find dxdu.dxdu=1+x21dx=(1+x2)du
Substitute x and dx: Substitute x and dx in the integral.The integral becomes:∫(tan(u)⋅u)/((1+tan2(u))3/2)⋅(1+tan2(u))du
Simplify integral: Simplify the integral.Since 1+tan2(u)=sec2(u), the integral simplifies to:∫(tan(u)⋅u)/(sec3(u))⋅sec2(u)du∫(tan(u)⋅u)/sec(u)du∫(sin(u)⋅u)/cos2(u)du
Perform integration by parts: Perform integration by parts.Let v=u and dw=cos2(u)sin(u)du. Then we need to find dv and w.dv=duw=∫cos2(u)sin(u)du
Find w: Find w by integrating dw.w=∫cos2(u)sin(u)duw=∫sec(u)tan(u)duw=sec(u)+C
Apply integration by parts: Apply integration by parts using the formula ∫udv=uv−∫vdu.∫cos2(u)sin(u)⋅udu=uv−∫vdu= u \cdot \sec(u) - \int \sec(u)\,du= u \cdot \sec(u) - \ln|\sec(u) + \tan(u)| + C
Substitute back x: Substitute back the original variable x. u=tan−1x, sec(u)=1+x2, tan(u)=x The integral becomes: tan−1x⋅1+x2−ln∣1+x2+x∣+C
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