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: Proving an equation

  1. Mar 11, 2008 #1
    1. The problem statement, all variables and given/known data
    Prove that tan^2θ - sin^2θ = tan^2θsin^2θ


    2. Relevant equations
    I'm not sure :S


    3. The attempt at a solution
    I have no idea
     
  2. jcsd
  3. Mar 11, 2008 #2

    Kurdt

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What is the definition of tan?
     
  4. Mar 11, 2008 #3
    tan = sin^2θ/cos^2θ

    ?
     
  5. Mar 11, 2008 #4

    Kurdt

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    [tex] \tan (\theta) = \frac{\sin(\theta)}{\cos(\theta)} [/tex]

    so

    [tex] \tan^2 (\theta) = \frac{\sin^2(\theta)}{\cos^2(\theta)} [/tex]

    You will then need to manipulate one side until it equals the other using basic trigonometric identities.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook