Hey guys would love any help on this problem!

Integral of 4x^2 / (25-x^2)^1/2

x=5sintheta

dx = 5costheta

doing some plugging in and cancelling I get...

integral (100sin^2theta)

sin^2theta = 1-2costheta / 2

So now I have...

50theta - 100sintheta .... Now I'm stuck, I know I have to eventually use a triangle but I'm not sure to make the 50theta go away.

Would appreciate any help !