Question

Draw the graphs of y = cos x and y = cos2x in [0,2π] on the same axes.

Answer 1

For cosx

x	π/6	π/3	π/2	π	3π/2	2π
cosx	√3/2	1/2	0	-1	0	1

For cos(2x)

x	π/6	π/3	π/2	π	3π/2	2π
cos(2x)	1/2	-1/2	-1	1	-1	1

The graph is:-

Blue line depicts curve cos(2x) 

Purple lines depict cos(x).