1. ## Solving Trigonometric Equation

Find exact solotions.

2cosx+3tanx=0
2cosx+3sinx/cosx=0 *cosx
2cos^2x+sinx=0 ***Im stuck here any hints, I tried to use the double angel formula but its cos 2x not 2cosx! any hints!

2. Originally Posted by jepal
Find exact solotions.

2cosx+3tanx=0
2cosx+3sinx/cosx=0 *cosx
2cos^2x+sinx=0 ***Im stuck here any hints, I tried to use the double angel formula but its cos 2x not 2cosx! any hints!
$\frac{2\cos^2{x}}{\cos{x}} + \frac{3\sin{x}}{\cos{x}} = 0$

$2\cos^2{x} + 3\sin{x} = 0$

$2(1 - \sin^2{x}) + 3\sin{x} = 0$

solve the quadratic for $\sin{x}$