Question

What is the sum and difference of sin 165 degrees?

Answer 1

I'm not quite sure i understand what you really want, but
here's my shot:

`sin165` could also be written as `sin(120+45)`

and so

`sin126= sin(120+45)= sin120cos45+sin45cos120`

`sin165` as a difference is

`sin(210-45) -=sin210cos45-sin45cos210`