Use an identity to write the expression as a single trigonom

Use an identity to write the expression as a single trigonometric function or as a single number.

4 sin 2x cos 2x

Select one:

a. cos 4x

c. 2 sin 4x

d. cos 8x

Solution

4 sin 2x cos 2x

=2(2 sin 2x cos 2x)

formula: 2sinacosa= sin2a

=2(sin (2*2x))

=2sin(4x)

option C