Logarithm rule

[nosit]

Hello,
As we know:

Ln A.B = Ln A + Ln B

As you can see in the picture attached, my teacher applied this rule as sigma is out of the root.

I do not understand why the sign before Ln sigma is minus and not plus (I highlighted in yellow)

Is there anyone who could help me on understand why?

 

[pka]

Well, I find your handwriting almost impossible to read.
That said, I think that it is
\({\large\bf-}\ln(\sqrt{2\pi}\sigma)={\large\bf-}\left[\ln(\sqrt{2\pi})+\ln(\sigma)\right]={\large\bf-}\ln(\sqrt{2\pi}){\large\bf-}\ln(\sigma)\)

 

[nosit]

Thank you!