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Math Help - C3 Trigonometry Question

  1. #1
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    C3 Trigonometry Question

    Here is a question, I've got an answer to it but I think its wrong

    a) prove that (done)



    b) verify that

    is a solution to the equation



    Does this rearrange to, using part (a), so, , which is correct??

    c) Using your result in part (a), or otherwise, find the other two solutions, , of the equation using

    For this I said that this meant that and the inverse tan of 0 = 0

    So, using the general solution for tan, and the fact that

    I got the answers 0 and 360, but I'm doubtful as the range is with no 'greater/less than or equal to' in there??
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  2. #2
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    London
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    Re: C3 Trigonometry Question

    Hello there, it is sufficient for part b) just to check that the LHS and the RHS agree. So considered separately, when theta=180 , the LHS sin(360)=0 and the RHS 2-2cos(360) = 0. This shows that theta=180 is a solution; therefore, there is no need for arrangement.

    For part c), I think you have a made a small mistake when rearranging - it should be 1= (2-2 cos(2 theta)) / ( sin 2 theta) which gives tan theta = 0.5.

    Hope this is helpful
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