Question

tg(a) = ? если 45 sin^2(a)+11 cos^2(a)=20 и (a)принадлежит(п/2;п)

Answer 1

45-45cos^2a+11cos^2a=20

25=34cos^2a

cos^2a=25/34

sin^2a=1-25/34=9/34

sina>0 cosa<0 tga<0

tga=3/5