Question

Basic trigonometric values.

Answer 1

first one is 0.997652127587
second one is 0.0684852708385

Answer 2

both = -
`(√(2) )/(2)`

Explanation:

`(5\pi )/(4)` is an angle in the 3rd quadrant where both sin and cos < 0

The related acute angle is
`(\pi )/(4)` , then

cos (
`(5\pi )/(4)` ) = - cos (
`(\pi )/(4)` ) = -
`(1)/(√(2) )` = -
`(√(2) )/(2)`

sin (
`(5\pi )/(4)` ) = - sin (
`(\pi )/(4)` ) = -
`(1)/(√(2) )` =
`(√(2) )/(2)`