Question

How do you find the exact value of `cos[ arctan (-4/3) - arcsin (3/5) ]`?

Answer 1

Zero.

Explanation:

You may use calculator
`tan x = -4/3` --> `x = 126.86` (or `-53.14`)
`sin y = 3/5` -->`y = 36^@86`
`x - y = 90^@`

`cos 90^@ = 0`