6. Trigonometric Identities and More Equations

Find the exact value of each expression.

sin (13π/12)

Find the exact value of each expression. (Do not use a calculator.)

cos (-7π/12)

Find the exact value of each expression.

tan (5π/12)

Find the exact value of each expression. (Do not use a calculator.)

cos (7π/9) cos (2π/9) - sin (7π/9) sin (2π/9)

Find the exact value of each expression.

sin (π/12)

Write each function value in terms of the cofunction of a complementary angle.

sin 15°

Find the exact value of each expression.

sin (- 5π/12)

Write each function value in terms of the cofunction of a complementary angle.

sin (2π/5)

Find the exact value of each expression.

tan (-7π/12)

Write each function value in terms of the cofunction of a complementary angle.

sin 142° 14'

Find the exact value of each expression.

sin (-13π/12)

Write each function value in terms of the cofunction of a complementary angle.

cot (9π/10)

Find the exact value of each expression. See Example 1.

sin 40° cos 50° + cos 40° sin 50°

Use the given information to find sin(x + y), cos(x - y), tan(x + y), and the quadrant of x + y.

sin x = 3/5, cos y = 24/25, x in quadrant I, y in quadrant IV

Write each function value in terms of the cofunction of a complementary angle.

tan 174° 03'