6. Trigonometric Identities and More Equations

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'

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

sin 5π/9 cos π/18 - cos 5π/9 sin π/18 .

Use the given information to find sin(x + y).

sin y = - 2/3 , cos x = - 1/5, x in quadrant II, y in quadrant III

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

sin 98.0142°

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

[tan 80° - tan(-55°)]/[ 1 + tan 80° tan(-55°)]

Use the given information to find sin(x + y).

cos x = 2/9, sin y = - 1, x in quadrant IV, y in quadrant III