1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Help with Integration

  1. Sep 29, 2009 #1
    1. The problem statement, all variables and given/known data
    1/sqrt(cos[2x]) from theta prime to pi/4

    2. Relevant equations
    Your basic trig identities:
    cos[2x]= 2cos^2[x]-1 = 1- 2sin^2[x] = cos^2[x]-sin^2[x]
    sin^2[x]+cos^2[x] = 1
    sin[2x] = 2sin[x]cos[x]

    Apparently, you're supose to manipulate so that you can do a substitution to eliminate all trigonometric terms, i.e. cosx, sinx, and whatever may come up. Then, since a substitution occurred, you can then change the bounds of integration.

    It should be similar to integrating 1/cosx by manipulation and substitution.

    3. The attempt at a solution

    Well, the first thing for me was trying to get rid of the square root in the denominator, multiplying top and bottom by cos[2x] everything i seem to have done thus far, ends up going in circles...
    Last edited: Sep 29, 2009
  2. jcsd
  3. Sep 29, 2009 #2

    This doesn't have an elementary antiderivative...
  4. Sep 29, 2009 #3
    I'm not sure about this question, but from what I was told, you have to use identities and manipulation in order to get it into a form that substitution is possible...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook