# Thread: trig problem involving double angle forumlas

1. ## trig problem involving double angle forumlas

in the problem in the above picture, how did they get from $2cox+2sinxcox=0$ to $2cosx(1+sinx)=0$?

2. ## Re: trig problem involving double angle forumlas

Hey kingsolomonsgrave.

They are factoring out cos(x) of both sides. Remember that in distributive law if you have ab + ac, then you can factor this out to get a(b+c).

3. ## Re: trig problem involving double angle forumlas

OH! of course, thanks!