Question Number 16406 by liday last updated on 21/Jun/17
$$\mathrm{D}=\left\{\left({x},\mathrm{y}\right)\mid\mid{x}\mid+\mid\mathrm{y}\mid\leqslant\mathrm{1},\mid{x}\mid+\mid{y}\mid\geqslant\mathrm{0}.\mathrm{5}\right\} \\ $$$$\underset{\mathrm{D}} {\int\int}\mathrm{ln}\:\left({x}^{\mathrm{2}} +{y}^{\mathrm{2}} \right){dxdy} \\ $$$$\left.\mathrm{a}\right)\geqslant\mathrm{0}; \\ $$$$\left.\mathrm{b}\right)\leqslant\mathrm{0}; \\ $$$$\left.\mathrm{c}\right)=\mathrm{0}; \\ $$$$\left.\mathrm{d}\right)\mathrm{non}-\mathrm{existent}. \\ $$