# Math Help - inverse trigonometric functions

1. ## inverse trigonometric functions

Just need a little help starting out these problems

Solve each equation in the interval indicated:

1.) tanx-2cosxtanx=0 ; [0, 360)
2.) 2sinx+1=cscx ; [0, 360)
3.) sin2x=-sinx ; [0, 360)
4.) sin2x=-1/2 ; [0, 360)

i appreciate the help

2. ## 1.) tanx-2cosxtanx=0 ; [0, 360).

solve each equation in the interval indicated:

1.) tanx-2cosxtanx=0 ; [0, 360)

factor out $tanX$

$tanX(1-2cosX) = 0$

then solve for $tanX = 0$

$tanX = 0$ at $\pi$ and $0$

solve for $(1-2cosX) = 0$

if $cosX = \frac{1}{2}$
then $(1-2cosX)$ will go to 0

so $cosX^{-1}(\frac{1}{2}) = \frac{\pi}{3}$ and $\frac{5\pi}{3}$

so x = $\pi , 0 ,\frac{\pi}{3}, \frac{5\pi}{3}$,