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[m]V_{Ox}=π ∫ ^{π}_{0}(2sinx)^2dx=4π ∫ ^{π}_{0}sin^2xdx=4π ∫ ^{π}_{0}\frac{1-cos2x}{2}dx=2π ∫ ^{π}_{0}(1-cos2x)dx=2π(x-\frac{1}{2}sin2x)| ^{π}_{0}=2π(π-0)=2π^2[/m]
