Question

Which is the graph of the given function?

Answer 1

ANSWER

The correct choice is A.

EXPLANATION

The given cosine function is:

$f(t) = 2 \cos( - 4t)$

This function has an amplitude of 2.

Hence it must have range,

-2≤f(t)≤2

It has a period of

$\frac{\pi}{2}$

Hence the function must complete one cycle on the interval,

[0,½π],

[½π,π],

etc.

The negative sign shows a reflection in the y-axis but since the cosine function is even, the function retraces itself.

The correct choice is A