1.   If sin = and has its terminal side in the first quadrant, find the exact value of cos 2.
    A. B.
    C. D. 1
    Hint

  2.   Use a half-angle identity to find the exact value of sin 67.5°.
    A. B.
    C. D.
    Hint

  3.   Find sin 2 if sin = and 0° < < 90°.
    A. B.
    C. D.
    Hint

  4.   If cos = and has its terminal side in the first quadrant, find the exact value of cos .
    A. B.
    C. - D. -
    Hint

  5.   Find the value of tan 2 if sin = and 0 < < .
    A. B.
    C. - D.
    Hint