Angle addition formulas (11:06) Formulas for
,
,
,
.
Using the cosine angle addition formula (5:13) Given a right triangle
and the lengths of its sides, find the cosine of
.
Using the cosine double-angle formula (3:27) Given a right triangle
and the lengths of its sides, find the cosine of
.
Finding trigonometric values using angle addition formulas (8:34) Find
.
- * Practice: Find trigonometric values using angle addition formulas. (4 problems)