- #1

- 59

- 0

## Homework Statement

How to get from

[tex]\sqrt{2+2cosx}[/tex]

to

2cos(x/2)

## The Attempt at a Solution

I'm pretty much stuck on this.

I can only see that is simplifies by taking out the common factor 2, which isnt correct.

- Thread starter Jenkz
- Start date

- #1

- 59

- 0

How to get from

[tex]\sqrt{2+2cosx}[/tex]

to

2cos(x/2)

I'm pretty much stuck on this.

I can only see that is simplifies by taking out the common factor 2, which isnt correct.

- #2

rock.freak667

Homework Helper

- 6,230

- 31

Well id cos2x=2cos^{2}x-1, then cosx=2cos^{2}(x/2)-1

- #3

- 59

- 0

Yup, thanks!

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