I want you to check my depiction of the region shown below of multiple integral is correct or not. I think that it seems correct but cannot have a strong confidence.
$$ A:=\left\{(x,y)\in\mathbb{R^2}~\Bigg|~-{1\over 2}\leq y\leq x\leq{1\over 2}\right\} $$
$$\begin{align} -{1\over 2}\leq y\leq x\leq{1\over 2}&\equiv\left(-{1\over 2}\le y\le x\right)\land\left(-{1\over 2}\le x\le{1\over 2}\right)\\&\land\left(-{1\over 2}\le y\le{1\over 2}\right)\land\left(y\le x\le{1\over 2}\right) \end{align}$$
The domain is given by $3$ conditions
$\cdot\ \ $ $y \ge - \frac{1}{2}$
$\cdot\ \ $ $ y \le x$
$\cdot\ \ $ $x \le \frac{1}{2}$
so a triangle. Yes, the picture is OK.