Results 1 to 4 of 4

Math Help - trig problem

  1. #1
    Newbie
    Joined
    Nov 2008
    Posts
    17

    trig problem

    hi ive been given this question and im not sure how to do it.

    1. a) Prove that cosec^4 x - cot^4 x = cosec^2 x + cot^2 x
    b) solve for 90 degrees< x < 180 degrees

    cosec^4 x - cot^4 x = 2 - cot x

    thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Dec 2008
    Posts
    1
    Quote Originally Posted by brooksy View Post
    hi ive been given this question and im not sure how to do it.

    1. a) Prove that cosec^4 x - cot^4 x = cosec^2 x + cot^2 x
    b) solve for 90 degrees< x < 180 degrees

    cosec^4 x - cot^4 x = 2 - cot x

    thanks
    cosec^4x-cot^4x=(cosec^2x)^2-(cot^2x)^2
    =(cosec^2x+cot^2x)(cosec^2x-cot^2x)
    =(cosec^2x+cot^2x)
    {a^2-b^2=(a-b)(a+b) and cosec^2x-cot^2x=1}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Nov 2008
    Posts
    17

    thanks

    thanks for that. does anyone know how to do part 2. cheers
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by brooksy View Post
    hi ive been given this question and im not sure how to do it.

    b) solve for 90 degrees< x < 180 degrees

    cosec^4 x - cot^4 x = 2 - cot x

    thanks

    cosec^4x-cot^4x=2-cot x
    cosec^4x-(cosec^4x-1)=2-cot x
    1=2-cot x
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Trig word problem - solving a trig equation.
    Posted in the Trigonometry Forum
    Replies: 6
    Last Post: March 14th 2011, 07:07 AM
  2. Replies: 3
    Last Post: January 2nd 2011, 08:20 PM
  3. Trig. Problem
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: January 21st 2010, 02:13 PM
  4. trig problem
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: May 13th 2009, 06:28 PM
  5. trig problem
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: April 1st 2008, 02:16 AM

Search Tags


/mathhelpforum @mathhelpforum