Вычислите (2-5cos2a) / (6+10sin2a) - (13+3tg2a) / (10cos2a-15sin2a) если tga=2.

Cos²a=1: (1+tg²a) = 1: (1+4) = 1/5

cosa=1/√5

sina=√ (1-cos²a) = √ (1-1/5) = 2/√5

cos2a=cos²a-sin²a=1/5-4/5=-3/5

sin2a=2sinacosa=2*1/√5*2/√5=4/5

tg2a=sin2a/cos2a=-2/3

(2+3) / (6+8) - (13-2) / (-6-12) = 5/14+11/18 = (45+77) / 126=122/126=61/63