I'm at a loss with this question: Could I get some pointer please?
By using substitution t = tanx evaluate the following definite integral:
Limits zero to pi/4
I = 1/(9((cosx)^2) - (sinx)^2) dx
Apologies for the notation (or lack of)
I'm stuck at getting this into a solveable integral
brackets indicate, rather...
integrate 1/(9 cos^2 x - sin^2 x) - Wolfram|Alpha
Click on 'show steps'. Basically, use pythag to write cos in terms of sin, then use the indentity
then substitute x = 2 arctan u, which is called the Weierstrass sub