1. tan(x+(pi/2)) = -cotx

2. cos^2(x) = csc^2(x)-cot^2(x) / sec^2(x)

3. cosx + cosxtan^2(x) = secx

I'm just not good with this stuff. I tried expanding the left side of the first one using sum and difference formulas and got no where with it, and for the other two I just got everything in terms of sin and cos and got even more lost. Any help is greatly appreciated.