let description = [{
Given an input tensor, this function computes cosine of every
  element in the tensor. Input range is `(-inf, inf)` and
  output range is `[-1,1]`. If input lies outside the boundary, `nan`
  is returned.

  ```python
  x = tf.constant([-float("inf"), -9, -0.5, 1, 1.2, 200, 10000, float("inf")])
  tf.math.cos(x) ==> [nan -0.91113025 0.87758255 0.5403023 0.36235774 0.48718765 -0.95215535 nan]