Question

tga2 ;ctg2 a если tg a = 2,4​

Answer 1

Ответ:

tg2α= - 120/119

ctg 2α= -119/120

Решение:

$tg2\alpha =\frac{2tg\alpha }{1-tg^2\alpha } =\frac{2*2,4}{(1-2,4)(1+2/4)}=\frac{2*2,4}{(-1,4)*3,4}=-\frac{120}{7*17} =-\frac{120}{119}$

$ctg2\alpha =\frac{1}{tg2\alpha }=-\frac{119}{120}$