Question

How to solve this~~ (see attachment soon)

Answer 1

\[\int\limits_{?}^{?} x \sqrt{4-x^{4}} dx\]

Answer 2

i set u=x\[1/2 \int\limits_{}^{} \sqrt{4-u^{2}} du\]^2 than i got

Answer 3

u =x^2

Answer 4

Do a trig sub, u=sin(theta)

Answer 5

du=cos(theta)dtheta

Answer 6

Woops, u=2sin(theta). Sorry

Answer 7

You can directly use formula...

Answer 8

wait~ why u=2sin (theta)?

Answer 9

Because then you can factor out 4 from the radical.