HEY GUYS I HATE TRIG

I have 6 problems to do and I don't remotely understand any of them. Here are the first two:

1) Simplify:

tan (2 arccos (x/3))

Your final answer is not supposed to contain any trigonometric or inverse trigonometric functions.

2) Solve the equation in the interval [0,2pi]. If there is more than one solution write them separated by commas.

(sin (x))^2 = 1/36

I "learned" trig in high school, but apparently I didn't understand it. Halp.

1) [2x sqrt(9 - x^2)]/(2x^2 - 9)
2) ±arcsin(1/6)

Idiot.

Number 1 is pretty obscure.
http://en.wikipedia.org/wiki/Trigonometric_identity#Inverse_trigonometric_functions is a good reference to find the answer.

yes?