Question

How do you find the amplitude and period of `y=-3cos(2t)`?

Answer 1

`"amplitude "=3," period "=pi`

Explanation:

The standard form of the `color(blue)"cosine function"` is.

`color(red)(bar(ul(|color(white)(2/2)color(black)(y=acos(bx+c)+d)color(white)(2/2)|)))`

`"where amplitude "=|a|," period "=(2pi)/b`

`"phase shift "=-c/b" and vertical shift "=d`

`"here " a=-3,b=2,c=0,d=0`

`rArr"amplitude "=|-3|=3" and period "=(2pi)/2=pi`