`y = (5/3)cos(4x/5)` Find the period and the amplitude

Expert Answers
caledon eNotes educator| Certified Educator

Formula for amplitude: if y = a cos bx, amplitude is the absolute value of a

Amplitude of 5/3

Formula for period: if y = a cos bx, period is 2pi/b

Rearrange to 2pi x 5/4

Period of 2.5`pi`

kspcr111 | Student

`y = (5/3)cos(4x/5)`

the general form is `y= a cos(bx)`

on comparing with the above equation with the general form we get

the amplitude is `|a| = (5/3)`

and the period for the cos is  `(2* pi) /|b| = (2pi)/(4/5) = 5pi/2`