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    Given that cotx = -(Root3), and that 90<x<180, find the exact value of

    a) sinx
    b) cosx
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    Do cot^-1 (-Root3) in your calculator. Take the value of x between 90 and 180 that satisfies this. Put it back into a and b.
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    What have you gotten so far? Perhaps put some of your working here so far or your plan on what to do?

    Anyway, I suggest you start by converting cotx to 1/tanx first to find the acute angle x. (Some algebraic rearranging should do the trick)

    Then consider the quadrant you are given (90<x<180) and whether sinx and cosx are positive or negative in that quadrant.
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    (Original post by iAre Teh Lejend)
    Given that cotx = -(Root3), and that 90<x<180, find the exact value of

    a) sinx
    b) cosx
    \cot x = \frac{1}{\tan x}.

    Multiply by tan x and divide by -\sqrt 3.

    a) using your calculator, do the inverse tan and then find sin x
    b) do the same as in a) but find cos x.
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    Thanks, I realised how to do this straight after i posted this thread. I was having a dumb moment.
 
 
 
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