How do you find the domain and range of #(1/2)cos2x#?

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Answer 1 · 2017-10-08T08:27:23

The domain is #x in RR#
The range is #y in [-1/2, 1/2]#

The domain of the #cos(2x)# is #x in RR#

To calculate the range, proceed as follows

Let #y=1/2cos(2x)#

#-1<=cos(2x)<=1#

and

#-1/2<=1/2cos(2x)<=1/2#

#-1/2<=y<=1/2#

The range is #y in [-1/2, 1/2]#