Question

Which graph represents f(x)=−2cos(4πx)?

Answer 1

the last one (bottom right)

Explanation:

4×pi is the same as twice around the whole circle to the beginning. it is the same as 0°, and cos(0) = 1, and then -2×cos(0) = -2

so, we only need to look, where the function reaches -2.

it should be at x = 0, x = 0.5 and x = 1.