Determine all the possible values where 0 degree <= x <= 360 degree such that;

sin x sec x - 3 sin x = 0

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- Apr 15th 2013, 05:33 PMchoi105Please help me how to solve this question.
Determine all the possible values where 0 degree <= x <= 360 degree such that;

sin x sec x - 3 sin x = 0

- Apr 15th 2013, 05:40 PMchiroRe: Please help me how to solve this question.
Hey choi105.

Please show us what you have tried. - Apr 15th 2013, 05:55 PMchoi105Re: Please help me how to solve this question.
sin x sec x - 3 sin x = 0

sin x 1/cos x - 3 sin x = 0

sin x - 3 sin x = cos x

then i not sure the step correct or not... - Apr 15th 2013, 06:45 PMchiroRe: Please help me how to solve this question.
Hint: Try thinking in terms of tan(x).

- Apr 15th 2013, 07:04 PMProve ItRe: Please help me how to solve this question.
First of all, your third line is incorrect, since when you multiply everything through by $\displaystyle \cos{(x)}$ you're supposed to get $\displaystyle \displaystyle \sin{(x)} - 3\sin{(x)}\cos{(x)} \ 0$.

Anyway, you should factorise the entire expression first and set each factor equal to 0.

$\displaystyle \displaystyle \begin{align*} \sin{(x)}\sec{(x)} - 3\sin{(x)} &= 0 \\ \sin{(x)} \left[ \sec{(x)} - 3 \right] &= 0 \\ \sin{(x)} = 0 \textrm{ or } \sec{(x)} - 3 &= 0 \end{align*}$

Go from here...