Graph of Trigo Func.

Can someone help me.. please (Crying)
What's the graph of:
1. -cos2x
2. 2cos(3x+pi/2)

thanks..(Bow)

WolframAlpha to the rescue. Although, these are straight-forward enough plots that you should be able to do them without technology. You need to know how scaling affects a function, both in the independent and dependent variable. You also need to know how an offset affects a function, both in the independent and dependent variable.