Sum/Difference Identities Practice

Front

What is the cosine of the sum of two angles?

Back

The cosine of the sum of two angles is given by the identity: cos(A + B) = cos(A)cos(B) - sin(A)sin(B).

Front

What is the sine of the sum of two angles?

Back

The sine of the sum of two angles is given by the identity: sin(A + B) = sin(A)cos(B) + cos(A)sin(B).

Front

What is the sine of the difference of two angles?

Back

The sine of the difference of two angles is given by the identity: sin(A - B) = sin(A)cos(B) - cos(A)sin(B).

Front

What is the cosine of the difference of two angles?

Back

The cosine of the difference of two angles is given by the identity: cos(A - B) = cos(A)cos(B) + sin(A)sin(B).

Front

Evaluate cos(175°)cos(55°) + sin(175°)sin(55°).

Back

cos(120°).

Front

Evaluate cos(70°)cos(40°) - sin(70°)sin(40°).

Back

cos(110°).

Front

Evaluate sin(5π/12)cos(π/4) - cos(5π/12)sin(π/4).

Back

1/2.

Front

What is the value of cos(75°) using sum or difference identities?

Back

cos(75°) = cos(45° + 30°) = cos(45°)cos(30°) - sin(45°)sin(30°).

Front

Evaluate sin(96°)cos(24°) + cos(96°)sin(24°).

Back

sin(120°).

Front

What is the relationship between sine and cosine for complementary angles?

Back

sin(θ) = cos(90° - θ) and cos(θ) = sin(90° - θ).