Trigonometric Identities - Sum & Difference Identities

Calculate the sin(15°)

• sin(45°)cos(30) - sin(30°)cos(45°)

• sin(45°)cos(30) + sin(30°)cos(45°)

• cos(45°)cos(30) - sin(30°)sin(45°)

• cos(45°)cos(30) + sin(30°)sin(45°)

Calculate the cos(75°)

• sin(45°)cos(30) - sin(30°)cos(45°)

• sin(45°)cos(30) + sin(30°)cos(45°)

• cos(45°)cos(30) - sin(30°)sin(45°)

• cos(45°)cos(30) + sin(30°)sin(45°)

If the sin(A) = 5/13, calculate the cos(A).

Note: sin²(x) + cos²(x) = 1

Write these numbers down, you will need them later.

• 12/13

• 4/5

• 3/5

• 7/25

If the cos(B) = 4/5, calculate the sin(B).

Note: sin²(x) + cos²(x) = 1

Write these numbers down, you will need them later.

• 12/13

• 4/5

• 3/5

• 7/25

Calculate sin(A - B)

• -16/65

• 56/65

• -48/65

• 72/65

Calculate sin(A + B)

• -16/65

• 56/65

• -48/65

• 72/65

Calculate cos(A + B)

• -16/65

• 56/65

• -48/65

• 72/65

Calculate cos(A - B)

• -16/65

• 56/65

• -48/65

• 72/65

Which of the following is equivalent to:

sin(40°)cos(80°) + sin(80°)cos(40°)

• sin(40°)

• sin(120°)

• cos(40°)

• cos(120°)

Which of the following is equivalent to:

cos(50°)cos(70°) + sin(50°)sin(70°)

• sin(20°)

• sin(120°)

• cos(20°)

• cos(120°)