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!

Isabel