Half-Angle Identities

Question 1

cos(x/2)=

Answer 1

+/- √ 1+cos(x)/2

Question 2

sin(x/2)=

Answer 2

+/- √ 1-cos(x)/2

Question 3

tan(x/2)=

Answer 3

+/- √1-cos(x)/1+cos(x)

sin(x)/ 1+cos(x)

1-cos(x)/sin(x)