Solve these over the domain 0≤a≤2pi:
3cos^2a-5cosa-1=3sin^2a
and 1/cos^2a+1-3tan^2a=0

I'm not sure what to do for either of these questions, can someone please help?

Question

Solve these over the domain 0≤a≤2pi: 
3cos^2a-5cosa-1=3sin^2a 
and 1/cos^2a+1-3tan^2a=0 

I'm not sure what to do for either of these questions, can someone please help?

dan815 · Answer

umm i think graph it

dan815 · Answer

between that interval

dan815 · Answer

oh nvm

tkhunny · Answer

Don't graph anything.

Hint: $\sin^{2}(x) = 1 - \cos^{2}(x)$

dan815 · Answer

do it like quadratic

dan815 · Answer

they just want the solution to be in that interval

thesecret20111 · Answer

Ok so like 3cos^2a-5cosa-1=3(1-cos^2(a))?

dan815 · Answer

ya and then just put it on 1 side and finish like ud solve a quadratice equation

thesecret20111 · Answer

Like 3cos^2a-5cosa-1-3-3cos^2(a)=0?

dan815 · Answer

ya but +3cos^2

dan815 · Answer

3cos^2a-5cosa-1-3+3cos^2(a)=0?
6cos^2a-5cosa-4=0

dan815 · Answer

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