Question

Sketch one cycle of the cosine function y= – cos 3θ

Answer 1

hmmm same as the other you posted... is the graph of y= cos(θ), but with a negative Amplitude of -1, and a B component of 3

let's check the period again
`\bf \cfrac{2\pi }{B}\iff \cfrac{2\pi }{3}`

so, is the same graph, with a period of
`\bf \cfrac{2\pi }{3}` and the negative amplitude will simply, retain the same midline, but the graph will be turned upside-down

Answer 2

Refer the attached graph

Explanation:

Given : Function
`y=-cos3\theta`

To Sketch the given function :

General form:
`y=\alpha cos(\beta\theta)`

where
`\alpha`=amplitude and
`(2\pi)/(\beta)` = period

According to question,
`y=-cos3\theta`

`\alpha`=-1 and
`(2\pi)/(3)` = period

From
`(0,(2\pi )/(3) )` cosine function sketch refer the attached graph .