Question

What are all the exact solutions of square root 2 cosx-1=0 for 0 less than or equal to x less than or equal to 2 pi ?Give your answer in radians.

Answer 1

The answer would be
B

Explanation:

What are all the exact solutions of square root 2 cosx-1=0 for 0 less than or equal to x less than or equal to 2 pi ?Give your answer in radians.

Answer 2

Answer:
`x=(\pi)/(4)\ or\ (7\pi)/(4)`

Explanation:

Given equation is

`√(2)\cos x-1=0`

solving this

`√(2)\cos x=1\\\cos x=(1)/(√(2))`

There can be two solution because
`0<x<2\pi`

`\cos x=\cos (\pi )/(4)\ or\ \cos (2\pi -(\pi)/(4))\\`

so,
`x=(\pi)/(4)\ or\ (7\pi)/(4)`