Question

How do you evaluate `csc[arc cos(-4/5)]`?

Answer 1

`5/3`

Explanation:

Let `a = arc cos (-4/5) in Q2`.

Then, #cos a = -4/5, sin a = sqrt(1-cos^2a)=3/5.

The given expression = csc a = 1/sin a=5/3#. .