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    Need to solve, range is -180<= 0 <= 180.
    I got 30 and -30, but there are 3 more values for which x is -180, 0 and 180 given in the answer. Can anyone explain why?
    Thanks
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    (Original post by Bilbao)
    Need to solve, range is -180<= 0 <= 180.
    I got 30 and -30, but there are 3 more values for which x is -180, 0 and 180 given in the answer. Can anyone explain why?
    Thanks
    Because you've seen \frac{sinx}{cosx} = sinx and cancelled them out instead of factoring them.

    An example would be x^2 = x. Dividing both sides by x yields x = 1. Factoring gives x^2 - x = x(x-1) = 0, giving x=0 also.

    Never cancel trig functions out through division, only when you have something like sinx = cosx, then you can make that tanx = 1.
 
 
 

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