Definite Integral (BIG BOSS)

[logicalman]

Who can solve or give hint for the following integral?

\int_0^4 3x \sqrt{5^2-x^2}dx :tongue: :eek:

[Hurkyl]

Try a technique you learned in class!

[mathlete]

Try u=5^2-x^2, which means du = -2xdx

[logicalman]

Thanks!

u^2=5^2-x^2 << This one works better. :tongue: