Find the period of each function, then sketch the graphs
a. y = 4sin2x
b. y = -4cos2x
I have no idea what that means..
You need to do some basic research on this topic. I Googled 'period of trig functions' and came up with several useful sites. Here are two of them. Here and here.
Have a close look at these, and then see if you can work out the answers to your questions. If you're not sure whether your answers are right, get back to us with your attempts and we'll let you know.