Question

помогите срочно! 2cos2a+3sin2a/5cos2a-sin2a

Answer 1

$\frac{2cos\, 2a+3sin2a}{5cos2a-sin2a}=[\, \frac{:\, cos2a}{:\, cos2a}\; ]=\frac{2+3tg2a}{5-tg2a}=\frac{3\cdot (tg2a+\frac{2}{3})}{-(tg2a-5)}=-3\cdot \frac{tg2a-5+5+\frac{2}{3}}{tg2a-5}=\\\\=-3\cdot \Big (1+\frac{17}{3(tg2a-5)}\Big )=-3-\frac{17}{tg2a-5}$