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!

Tan^2x =sec^2x-1 also: tan= sec -1 or am I missing something?

  1. Feb 17, 2015 #1
    A particular problem with factoring has both of these, one in the denominator and one in the numerator, if it were algebra it would look like: x^2-1/x-1. The trouble is I've forgotten how to simplify this. I'm on taptalk.)
  2. jcsd
  3. Feb 17, 2015 #2


    User Avatar
    Homework Helper

    Can you please make more sense of this. What is your problem exactly? And no, [itex]\tan{x}\neq \sec{x}-1[/itex]
  4. Feb 17, 2015 #3
    That just looks like gibberish on taptalk. Essentially it is Sec^2x-1/Secx-1 once a bit of factoring is done.
  5. Feb 17, 2015 #4


    User Avatar
    Homework Helper

    So you want to simplify this expression by factoring or any other means? Ok well, if we take a look at


    and then factor out 1/x giving us


    The cubic has no rational factors, so that is the best we can do. We're not completely at a loss with simplifying though.

    You know that


    so then use this to simplify your expression.
  6. Feb 17, 2015 #5
    This is my problem.
  7. Feb 17, 2015 #6
    I solved my problem... I was not removing the square when factoring. Always seems to be that kind of mistake that gets me.
  8. Feb 17, 2015 #7


    User Avatar
    Homework Helper

    Please use parentheses in future.

    is read as

  9. Feb 19, 2015 #8


    User Avatar
    Science Advisor

    [tex]\frac{x^2- 1}{x- 1}= \frac{(x- 1)(x+ 1)}{x- 1}= x+ 1[/tex] as long as x is not equal to 1.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook