# precal

posted by
**joy**
.

im taking test

need answer quick'

use the sum and difference identities to write the expression as the cosine of the angle. be sure to simplify the anglee:

cospi/9cospi/3-sin

pi/9sinpi/3

posted by
**joy**
.

im taking test

need answer quick'

use the sum and difference identities to write the expression as the cosine of the angle. be sure to simplify the anglee:

cospi/9cospi/3-sin

pi/9sinpi/3