№ 9.3.178
x^2/a^2 + y^2/b^2 = 1, y = -b, y = b вокруг оси Oy
[m]x^2=(1+\frac{y^2}{b^2})\cdot a^2[/m]
[m]V_{Oy}=π ∫ ^{b}_{-b}x^2dy=π ∫ ^{b}_{-b}(1+\frac{y^2}{b^2})\cdot a^2dy=πa^2(y+\frac{1}{b^2}\cdot \frac{y^3}{3})|^{b}_{-b}=[/m]