Double Integral Y2
1. **Problem statement:** Evaluate the double integral $$\iint_D y^2 \, dA$$ where $$D = \{(x,y) \mid -1 \leq y \leq 1, -y - 2 \leq x \leq y\}$$.
2. **Set up the integral:** The region $$D$$ is described by $$y$$ between $$-1$$ and $$1$$, and for each fixed $$y$$, $$x$$ ranges from $$-y - 2$$ to $$y$$.
3. **Integral expression:**
$$
\iint_D y^2 \, dA = \int_{y=-1}^1 \int_{x=-y-2}^y y^2 \, dx \, dy
$$
4. **Integrate with respect to $$x$$ first:** Since $$y^2$$ is constant with respect to $$x$$,
$$
\int_{x=-y-2}^y y^2 \, dx = y^2 \cdot \left(y - (-y - 2)\right) = y^2 (y + y + 2) = y^2 (2y + 2) = 2y^3 + 2y^2
$$
5. **Rewrite the integral:**
$$
\int_{-1}^1 (2y^3 + 2y^2) \, dy = 2 \int_{-1}^1 y^3 \, dy + 2 \int_{-1}^1 y^2 \, dy
$$
6. **Evaluate each integral:**
- $$\int_{-1}^1 y^3 \, dy = 0$$ because $$y^3$$ is an odd function over symmetric limits.
- $$\int_{-1}^1 y^2 \, dy = \left[ \frac{y^3}{3} \right]_{-1}^1 = \frac{1}{3} - \left(-\frac{1}{3}\right) = \frac{2}{3}$$
7. **Calculate the total:**
$$
2 \cdot 0 + 2 \cdot \frac{2}{3} = \frac{4}{3}
$$
**Final answer:** $$\boxed{\frac{4}{3}}$$