find the period and amplitude

Question

y = 3 cos 2x

Answer 1

  

The general form of cosine function is y = a cos bx , its period and amplitude are 2pi/b and |a| respectively.

The function is y = 3 cos 2x.

The period is 2pi/b.

= 2pi/2

= pi.

The amplitude is |a| = |3| = 3.

The period is pi and the amplitude is 3.