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# C3 trig help Urgent watch

1. Solve for 0< θ<360

Cos(θ-30) = 2Sinθ

2. (Original post by Rockyboy)
Solve for 0< θ<360

Cos(θ-30) = 2Sinθ

How so?

Then you can get out of it.
3. Dividing by an expression with just sin and cos to get tan is a handy trick like knowing lne=1. I forgot it was best to divide by cos when I was doing a past paper and did the whole Rsin(x+a) thing when you didn't have to.
4. (Original post by RDKGames)
How so?

Then you can get out of it.
Yes but what to i do after. Cuz i got

1+tan(θ)tan(30) =2sin( θ)
5. (Original post by Rockyboy)
Yes but what to i do after. Cuz i got

1+tan(θ)tan(30) =2sin( θ)
That's wrong.

So

Thus
Dividing by an expression with just sin and cos to get tan is a handy trick like knowing lne=1. I forgot it was best to divide by cos when I was doing a past paper and did the whole Rsin(x+a) thing when you didn't have to.
dont you lose a solution if you divide by sin/cos or does that not apply to this question?
7. (Original post by RDKGames)
That's wrong.

So

Thus
I got it thx
8. Never mind im being stupid. i get it now thank you very much
dont you lose a solution if you divide by sin/cos or does that not apply to this question?
Say if you had sinx+cosx=0 then the quickest approach is to divide by cosx. However yeah if possible you should always fractorise so if it was cos^2(x)+sinxcosx=0 you would factorise first to get cosx(cosx+sinx)=0 then say cosx=0 and cosx+sinx=0.
Say if you had sinx+cosx=0 then the quickest approach is to divide by cosx. However yeah if possible you should always fractorise so if it was cos^2(x)+sinxcosx=0 you would factorise first to get cosx(cosx+sinx)=0 then say cosx=0 and cosx+sinx=0.
ok thanks!

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