Question

I need help fast pleasee

Answer 1

y = - cos (
`(3)/(4)` x +
`(\pi )/(4)` )

Explanation:

y = A cos ( Bx + C) + D

Vertical shift D = 0

A = - 1

Compression / Stretching B

Period of given function is
`(8\pi )/(3)`

Period of cos x is 2π

`(8\pi )/(3)` =
`(2\pi )/(B)` ⇒ B =
`(3)/(4)`

Horizontal shift is C ÷ B

Horizontal shift of given function is
`(\pi )/(3)`

`(\pi )/(3)` = C ÷
`(3)/(4)` ⇒ C =
`(\pi )/(4)`

So, the equation of given function is

y = - cos (
`(3)/(4)` x +
`(\pi )/(4)` )