hi guys,

i have a problem with this trig equation.

1)5sinxcosx - sinx = 0

i tried divding this equation with cos turing the equation in terms of tan to solve it , i got tan = 4, but the angles i got didn't match the answer of the book.

2) tan(30 - x) = 2.

in this equation i don't know how to manipulate the range. i know how to do it when you have for example(x - 30 degress),

if say the range is -90 < x > 90

do i just simple do 30-(-90) and 30-90 ?

3) for the third question can someone prove this identity for me pls, i really have trouble proving it

sinxtanx + cosx = secx

thanks in advance