PreCal(Please help)
posted by Abbey .
1) Use the halfangle formulas to determine the exact values of the sine, cosine, and tangent of the angle.
67 degrees 30'

Use the half angle formulas at
http://www.sosmath.com/trig/douangl/douangl.html
The sine of the full angle (135 deg) is 1/sqrt2 and the cosing is 1/sqrt2