6. Trigonometric Identities and More Equations

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

cos 105° (Hint: 105° = 60° + 45°)

Find the exact value of each expression.

tan 285°

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

cos π/12

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)