10-3!!!!!

Soo today im going to do my blog on chapter 10 section 3! When i did my blog on chapter 10 section 1 last week you were able to tell that there were a few formulas well they also have a few formulas to go with chapter 10 section 3. So tonight i will begin with showing you all the formulas for double and half angles.

Half angle formulas:
sin(a/2)=+/-square root of (1-cosa)/2
cos(a/2)=+/-square root of (1+cosa)/2
tan(a/2)=1-cosa/sina
tan(a/2)=sina/1+cosa

Double angle formulas:
sin2a=2sinacosa
cos2a=cos^2-sin^2a
cos2a=2cos^2a-1
cos2a=1-2sin^2a
tan2a=2tana/1-tan^2a

So now that i have showed you all the formulas you need for this section i will do an example or 2 and show you how to use the formulas.

2sin30cos30
This is the first problem i will be showing you how to do. Some where in all these formulas there is one that relates to this problem! :sin2a=2sinacosa. There it is! yay!!!!
so then you will replace"a" with 30 and will end up with sin2(30) and that will give you sin60!!!!!

2tan80/1-tan^2(80)
this problem is similar to the one before you just fine the formula and replace.
tan2a=2tana/1-tan^2-> tan2(8)=tan160 degrees.