Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Help solving trigonometric equation?

  1. Aug 8, 2008 #1
    Can someone please give me some tips on how to solve this? :

    400*(2,2*cosV-1)*tanV=20*9,81, I am supposed to find V, but I can't see how to solve this equation.
  2. jcsd
  3. Aug 8, 2008 #2
    Does 2,2 represent 2.2 and 9,81 9.81? Show how much you've done already.
  4. Aug 8, 2008 #3
    Yes, i am sorry, I am not familiar with the correct way to write decimals.

    What I have done allready? I made this equation from a statics problem which required equlibrium of a disk with a spring around a quarter circle. I have tried checking the equation numerically and it gives the right answers, but I have no idea how I am supposed to solve the equation mathematically.
  5. Aug 8, 2008 #4
    It's ok I've seen them written that way. The main difficulty I'm having is dealing with these not so nice numbers. I figured I would write everything in terms of sin and cos which would bring me to 2.2sin(V)cos(V) = sin(V) + (9.81/20)cos(V). The left hand side is 1.1sin(2V) but I'm not certain about the right hand side.

    I'm not sure if there are better manipulations but if not a numerical solution will have to do.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Help solving trigonometric equation?