Integral Xsinx 121Abe
1. **State the problem:** We need to evaluate the definite integral $$\int_0^{\frac{\pi}{2}} x \sin x \, dx$$.
2. **Formula and method:** To solve this integral, we use integration by parts. The formula for integration by parts is:
$$\int u \, dv = uv - \int v \, du$$
3. **Choose parts:** Let
$$u = x \implies du = dx$$
$$dv = \sin x \, dx \implies v = -\cos x$$
4. **Apply integration by parts:**
$$\int_0^{\frac{\pi}{2}} x \sin x \, dx = \left. -x \cos x \right|_0^{\frac{\pi}{2}} + \int_0^{\frac{\pi}{2}} \cos x \, dx$$
5. **Evaluate the remaining integral:**
$$\int_0^{\frac{\pi}{2}} \cos x \, dx = \left. \sin x \right|_0^{\frac{\pi}{2}} = 1 - 0 = 1$$
6. **Evaluate the boundary term:**
$$-x \cos x \Big|_0^{\frac{\pi}{2}} = -\frac{\pi}{2} \cdot \cos \frac{\pi}{2} + 0 \cdot \cos 0 = 0 + 0 = 0$$
7. **Combine results:**
$$\int_0^{\frac{\pi}{2}} x \sin x \, dx = 0 + 1 = 1$$
**Final answer:** $$\boxed{1}$$