Precalc 11 – “Week 17”

This week in Precalculus 11 we learned about trigonometry. During the week we improved our understandings of trig and learned two new laws for trigonometry.

The first law is the Sine Law:

$\frac{a}{sinA}=\frac{b}{sinB}=\frac{c}{sinC}$

The Sine law is used for triangles with no angle being 90 degrees. It can only be used when A, a and either another side or another angle; A, B and c.

The second law is the Cosine Law:

$a^{2}=b^{2}+c^{2}-2bcCosA$

The Cosine Law can only be used for triangles that have the three sides or when a,c and B are known.