I'm quite confused on this question.

Limit Cos [ (pi * x) / (1- 4x) ]

X -> infinity

What I thought it was was to divide everything by x so it would be

Cos (pi / (1/x) - 4)

So as x -> inf 1/x = 0.

So the answer would be

Cos (pi / 4)

am I doing this right?