1. Set up integration by parts by identifying $u$ and $\frac{dv}{dx}$.
∫sin−12x dx=∫1⋅sin−12x dx
Let u=sin−12x⟹dxdu=1−(2x)22=1−4x22
Let dxdv=1⟹v=x
2. Apply the integration by parts formula $\int u \text{ d}v = uv - \int v \text{ d}u$.
∫sin−12x dx=xsin−12x−∫x(1−4x22) dx
=xsin−12x−∫1−4x22x dx
3. Evaluate the remaining integral using reverse chain rule (substitution) and add the constant of integration.
Consider ∫1−4x22x dx:
=−41∫−8x(1−4x2)−21 dx
=−41(21(1−4x2)21)=−211−4x2
Substituting this back:
∫sin−12x dx=xsin−12x−(−211−4x2)+C
=xsin−12x+211−4x2+C
Answerxsin−12x+211−4x2+C