Tính tích phân sau: <span class="katex-r" data-latex="displaystyle i∫_{mathcal{D}}(x^2+y^2right)^2 d x d y"></span>, ong đó <span class="katex-r" data-latex="displaystyle mathcal{D}:{beg∈{}{l}y ≤ x^2+y^2 ≤ 2 y x ≤ y ≤ st{3} x{}right."></span>