CAST

My thinking is that sinx -2cosx = 0

The question is to find x between 0 and 360 in:

sinx(sinx-2cosx)=0

I'm aware that I will get sinx=0

Then I will do sin^-1(0) = 0

And then get the values: 0, 180, 360 from the respective CAST diagram.

However, I must also get the other for cosx..

My thinking is that sinx -2cosx = 0

But that gets me cosx = (sin x) /2

From here I'm not sure what to do, any assistance would be greatly appreciated

$\sin x - 2\cos x = 0$

Gives

$\sin x = 2\cos x$

I suggest that you divide both sides of the equation by $\cos x$

If $\sin x - 2 \cos x =0$ then $\sin x = 2 \cos x$ and so you can find $\tan x$.

I thought that, but worried about cos x being equal to 0 and it therefore not working.

However I see now that it cannot, thank you very much!

Always good to check

you can do the division anyway, if there is a possibility of it =0, then you just write this as an option

however, as you have seen it cannot =0 in this case