x=sintheta, dx=cos theta d theta
intsqrt(3(1-sin^2theta))*cos theta d theta=intsqrt(3(cos^2theta)) cos theta d theta
=intsqrt3 cos theta cos theta d theta
=sqrt 3intcos^2 theta d theta
=sqrt3 int1/2 (cos2 theta+1) d theta
=sqrt3/2 int (cos2 theta+1) d theta
=sqrt3/2 [1/2 sin2theta+theta]
=sqrt3/4sin2theta+sqrt3/2 theta +C