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10.1

in this lesson, we are not allowed to use calculators.
we must also know the trig chart in order to do this lesson.
you must know these formulas:

cos(alpha +/- beta)= cos(alpha)cos(beta) +/- sin(alpha)sin(beta)

sin(alpha +/- beta)= sin(alpha)cos(beta) +/- cos(alpha)sin(beta)

alpha and beta come from the trig chart. you will either add or subtract them to get the angle needed.

Ex: Find the exact calue of sin15 degrees.

alpha=45
beta=30
45-30=15

sin(45-30)=sin45cos30-cos45sin30
=(square root of 2/2)(square root of 3/2)-cos(square root of 2/2)(1/2)

square root of 6/4 - square root of 2/4= square root of 6 - square root of 2/4

sin 15= square root of 6-square root of 2/ 4