Tori Holiday Blog #3

6 down, 1 to go!!

Section 10-1
Formulas:
cos(alpha +/- beta) cos alpha cos beta -/+ sin alpha sin beta
sin(alpha +/- beta) sin alpha cos beta +/- cos alpha sin beta

Examples:

Ex1:Find the exact value of sin15
sin(45-30)=sin45cos30-cos45sin30=
(√2/2)(√3/2)-(√2/2)(1/2)=
√6-√2/4

Section 10-2 ( same concept but tan instead)
Formula:
tan(alpha + beta)= tan (alpha) + tan (beta) / 1-tan(alpha) tan(beta)
tan(alpha - beta)= tan(alpha)- tan (beta) / 1+tan(alpha)tan(beta)

Ex2:Simplify: tan27+tan18/1-tan27tan18=
tan(27+18)=tan45
=1