1. ## Solving for theta

Ok.. so I've been stuck on a problem for a while now and have no clue how to even start this problem

it's 3sin^2X+5cosX=4

It would be much appreciated if someone could explain to me how I even start to solve this problem

2. Originally Posted by StephAnnie
Ok.. so I've been stuck on a problem for a while now and have no clue how to even start this problem

it's 3sin^2X+5cosX=4

It would be much appreciated if someone could explain to me how I even start to solve this problem
You need to use the Pythagorean identity

$\sin^2(x)=1-\cos^2(x)$ this reduces the equation to

$3(1-\cos^2(x))+5\cos(x)-4=0 \iff 3\cos^2(x)-5\cos(x)+1=0$

So this is quadratic in form. Can you finish from here

3. Thank you soo much for your help!!