Results 1 to 2 of 2

Math Help - 5 coshx + 4 sinh x =7

  1. #1
    Newbie
    Joined
    Mar 2009
    Posts
    9

    5 coshx + 4 sinh x =7

    I need help solving this equation

    5 coshx + 4 sinh x =7

    Any help would be greatly appreciated. Cheers!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Behold, the power of SARDINES!
    TheEmptySet's Avatar
    Joined
    Feb 2008
    From
    Yuma, AZ, USA
    Posts
    3,764
    Thanks
    78
    Quote Originally Posted by taichi2910 View Post
    I need help solving this equation

    5 coshx + 4 sinh x =7

    Any help would be greatly appreciated. Cheers!
    Using the definition of cosh and sinh will help simpilfy the problem

    5\left( \frac{e^{x}+e^{-x}}{2}\right)+4\left( \frac{e^{x}-e^{-x}}{2}\right)=7 \implies

    9e^{x}+e^{-x}=14

    Now this is quadratic in form if we multiply by e^{x} we get

    9(e^{x})^2+1=14e^{x} \iff 9(e^{x})^2-14e^{x}+1=0

    To simplify things let u=e^{x}

    9u^2-14u+1=0

    You should be able to finish from here. Good luck
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] | sinh (z) |^2 = sinh^2(x) + sin^2(y)
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: December 21st 2010, 02:23 PM
  2. Replies: 1
    Last Post: May 26th 2010, 12:30 PM
  3. Sinh and Skn
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: August 29th 2009, 06:24 AM
  4. sinh(x)
    Posted in the Calculus Forum
    Replies: 2
    Last Post: November 10th 2008, 04:16 PM
  5. sinh
    Posted in the Calculus Forum
    Replies: 2
    Last Post: June 19th 2008, 06:15 AM

Search Tags


/mathhelpforum @mathhelpforum