My honors

trig teacher junior year taught these to our class to help us remember the rules for

sine, cosine, and tangent of a sum. They got on our nerves after about the second time singing them, but we remembered those identities for the test.

Oh, the

sine goes sine cosine cosine sine

The sine goes sine cosine cosine sine

The

sign's the same in the sine, but it switches in the cosine

The sine goes sine cosine cosine sine

The

cosine goes cosine cosine sine sine

The cosine goes cosine cosine sine sine

The sign's the same in the sine, but it switches in the cosine

The cosine goes cosine cosine sine sine

Tan a tan a tan a

Plus tan b tan b tan b

All over all over all over

1 minus tan a times tan b

This is the sum of tangents

This is the sum of tangents

This is the sum of tangents

Unless tan a times tan b equals 1