Question

Do I have this one correct

Answer 1

Option B is correct

Explanation:

Given is a cos funciton.

Period = 3

Max = 20 and minimum =0

Hence centre line is y = 1/2 (max+min)

i.e. y =10 is the central line

Let the funciton be of the form

y = a cos (bx+C)+d

We got d = 10...i

Period =3

Hence b =
`(2\pi)/(3)` ... ii

Amplitude = a = distance of max from central line = 20-10 =10...iii

Since reflection over x axis, sign of a =negative

a=-10

Since no horizontal shift, c=0 ... iv

Put to gether the function is

`y=-10cos(2\pi x)/(3) +10`