# Trigonmetric integrals and substitutions

1. Sep 11, 2008

### graycolor

1. The problem statement, all variables and given/known data
integral of 83/((x^2)(100x^2-121)^(1/2))

2. Relevant equations
1+(tanx)^2=(secx)^2

(secx)^2-1=(tanx)^2

(x^2-a^2)^(1/2)

3. The attempt at a solution
moved 83 out of the integral tried converting the denominator to sec and then to tan, but not sure if that is right because of the 100.

2. Sep 11, 2008

### Dick

First substitute 11*u/10=x. Now take the 121 out of the radical and put it with your 83 (after you take the sqrt of course!). The meat of the integral is 1/(u^2*sqrt(u^2-1)). That looks like a sec substitution.