Ok..maybe not one more but three :)
I'm supposed to find all solution of the equation in the inverval [0, 2pi).
1. sin2x = - sqrt(3)/2.
I tried solving this one. I have something like this: 2pi/3 + npi and 5pi/12 + npi.
2. tan3x = 1
3. Sec 4x = 2
Thanks for all the help! :D