Trigonometry – Sum and Difference Formulas of Sine and Cosine

By | September 15, 2016

Sum and Difference Formulas of Sine and Cosine

In this tutorial student learn how to verify a trigonometric equation using trigonometric identities like the difference formula for sine and cosine.

Virginia Standards of Learning (SOL) T.5

Key Points of Knowledge

Sum and Difference Formulas

cos (α + β) = cos (α) cos (β) - sin (α) sin (β)

cos (α - β) = cos (α) cos (β) + sin (α) sin (β)

sin (α + β) = sin (α) cos (β) + cos (α) sin (β)

sin (α - β) = sin (α) cos (β) - cos (α) sin (β)

Pythagorean Theorem

a² + b² = c²

Pythagorean Triples

3, 4, 5

5, 12, 13

7, 24, 25 etc...

Quadrants on the Coordinate Plane

I, II, III, IV

Fraction Multiplication

Fraction Addition

More Examples