precal

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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

  • precal -

    You're taking a test? Do you want us to help you cheat??

    My, goodness, no!!

  • precal -

    hint:
    cos(A+B) = cosAcosB - sinAsinB

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