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Homework Help: Trig Functions- Could anyone tell me why my working is wrong?

  1. Sep 13, 2006 #1
    Trig Functions- Could anyone tell me why my working is wrong??

    the question seems simple..although i dont know what i am doin because it is obviously wrong!!!. thnkas heaps if anyone can help..

    solve
    2cosx-(sqrt(3))cosx sinx = 0 for (-pie<=x<=pie)

    what i was doin is dividing through by cos x, therefore i obtain:

    2-(sqrt(3))sinx= 0

    however this statement is flawed!!! since no value exists for sin x= 2/(sqrt(3))

    ?????it seems simple.. so wat am i doing wrong!!1
     
  2. jcsd
  3. Sep 13, 2006 #2
    if you copied the question right then yes sin x = 2/srqt3 is not possible

    however you CAN find answer for the cosine part
    cos x = 0 what values of x will do?
     
  4. Sep 14, 2006 #3
    yep got it now...instead i just did the follwing
    =
    cosx(2-(sqrt(3))sinx)=0
    therfore either cosx= 0 (as u stated above) or the other applies...which isnlt possible...so yeah obviously the answers are pie/2 and -pie/2
    thanks for your help!!!
     
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