integral question help!?

Question

please help me solve this integral..i am stuck

integral: square root of 9 +4x^2 dx

Answer 1

try taking the 9 out of the sqrt

3*sqrt(1+ (4/9)x^2) dx

then use the trig identity of 1 + tan^2 = sec^2

let tan@=(2/3)x

and do d@/dx on it

if i get a chance to dig further i will :p

Answer 2

try trigonometric substitution