Cot(A 15) - tan(A-15)
cos(A 15) / sin(A 15) - sin(A-15) / cos(A - 15)
[cos(A 15)cos(A-15) - sin(A-15)sin(A 15)] / [ sin(A 15)cos(A-15)
cos2A / sin(A 15)cos(A-15)
2cos2A / 2sin(A 15)cos(A-15)
2cos2A / [sin2A sin30]
2cos2A / [ sin2A 1/2]
2cos2A / [(2sin2A 1)/2]
4cos2A / (2sin2A 1)
Written on Feb. 7, 2019, 10:43 a.m.