Sum and Difference Identities

Front

What is the sum identity for cosine?

Back

The sum identity for cosine is: \( \cos(A + B) = \cos A \cos B - \sin A \sin B \)

Front

What is the difference identity for cosine?

Back

The difference identity for cosine is: \( \cos(A - B) = \cos A \cos B + \sin A \sin B \)

Front

What is the sum identity for sine?

Back

The sum identity for sine is: \( \sin(A + B) = \sin A \cos B + \cos A \sin B \)

Front

What is the difference identity for sine?

Back

The difference identity for sine is: \( \sin(A - B) = \sin A \cos B - \cos A \sin B \)

Front

What is the tangent of a difference identity?

Back

The tangent of a difference identity is: \( \tan(A - B) = \frac{\tan A - \tan B}{1 + \tan A \tan B} \)

Front

What is the tangent of a sum identity?

Back

The tangent of a sum identity is: \( \tan(A + B) = \frac{\tan A + \tan B}{1 - \tan A \tan B} \)

Front

How do you expand \( \sin(A + B) \)?

Back

To expand \( \sin(A + B) \), use the identity: \( \sin(A + B) = \sin A \cos B + \cos A \sin B \)

Front

How do you expand \( \cos(A + B) \)?

Back

To expand \( \cos(A + B) \), use the identity: \( \cos(A + B) = \cos A \cos B - \sin A \sin B \)

Front

What is the value of \( \cos 90^o \)?

Back

The value of \( \cos 90^o \) is 0.

Front

What is the value of \( \sin 90^o \)?

Back

The value of \( \sin 90^o \) is 1.