z=x^2+y^2
z=0
y=x
y=2x
x=1
[m]V= ∫∫_{D}(x^2+y^2)dxdy= ∫_{0} ^{1}( ∫_{x} ^{2x}(x^2+y^2)dy)dx=[/m]
[m]=∫_{0} ^{1}(x^2y+\frac{y^3}{3})|_{x} ^{2x}dx=∫_{0} ^{1}((x^2\cdot 2x+\frac{(2x)^3}{3})-(x^2\cdot x+\frac{x^3}{3}))dx=[/m]
считайте
....