Use half-angle formulas to find the exact value for the following

Question

cot 75 degrees

Answer 1

75 degrees is one-half of 150 degrees, and you should know the sin and cosine of that. Let A/2=75 so that A = 150. Then use this half angle formula for cot A/2

cot(A/2) = +/- (1 + cos A)/sin A

You will have to pick the sign to go with the quadrant. In the first quadrant, it is positive