Trig substitution (integration)

[joess]

Homework Statement

Homework Equations

The Attempt at a Solution

I'm not asking for someone to do the question for me but I was just wondering what I'm supposed to sub in. Do I put in

as if it was (x^2-9)^(1/2) or do I have to do something differently if there is a constant in front of the x^2? Thanks for any help.

 

[ChaoticLlama]

You are correct, secant is the correct trig function to use in this case.
However the coefficient is incomplete, you need to divide out the 4 as well.

 

[joess]

So is it x=(3/2)sec(theta) ?

 

[TD]

That's right! :)