double angle

It's sort of late,but i still managed to remember to do this ;)

The lesson learned this week included 10 new formulas in order to solve these problems. You could memorize them to study or use cards.

Here are all of the formulas used to solve these problems:

1. sin2alpha= 2sinalphacosalpha

2. cos2alpha= cos^2A-sin^2A

3. sin2alpha= 1-2sin^2A

4. sin2alpha= 2cos^2alpha-1

5. tan2alpha= 2tanalpha/1-tan^2alpha

6. sin alpha/2= +/- square root of 1-cosalpha/2

7. cos alpha/2= +/- square root of 1+ cosalpha/2

8. tan alpha/2= +/- square root of 1-cosalpha/1+cosalpha

9. square root of 1-cosalpha/1+cosalpha= sinalpha/1+cosalpha

10. sinalpha/1+cosalpha= 1-cosalpha/sinalpha

Example problem

1. 2sin(45)cos)

sin2(45)=sin(90)

You are just simplifying this problem.

1-cos(10)/ sin(10)

tan(10)/2=tan(5)

For this problem cos and sin turn into tan.

Simplify:

2cos^2(20)-1

cos2(20)= cos40

=4 square root of 5

LOOVEYALL:)