\[ \iint_{D} x y d x d y=\int_{0}^{1} \int_{0}^{x} x y d y d x=\left.\int_{0}^{1} \frac{x y^{2}}{2}\right|_{0} ^{x} d x=\int_{0}^{1} \frac{x^{3}}{2} d x=\left.\frac{x^{4}}{8}\right|_{0} ^{1}=\frac{1}{...∬Dxydxdy=∫10∫x0xydydx=∫10xy22|x0dx=∫10x32dx=x48|10=18. \ iiint\ int_ {D}\ izquierda (x^ {2} +y^ {2} +z^ {2} -t^ {2}\ derecha) d x d y d z d t &=\ int_ {0} ^ {1}\ int_ {-1} ^ {1}\ int_ {-2} ^ {2}\ int_ {0} ^ {2}\ int_ {0} ^ {2}}\ izquierda (x^ {2} +y^ {2} +z^ {2} -t^ {2}\ derecha) d t d z d y d x\\
