Question

x apartine (90*;180*):sin x =radical 5/3, sa se afle tg x ,ctg 2x

Answer 1

sin x=√5/3

tg x=sinx/cosx

cosx=√(1-sin²x)=√(1-5/9)=√(4/9)=2/3

tg x=(√5/3) /(2/3)=√5/2

ctg 2x=(ctg²x-1)/2 ctg x

ctg x=1/tg x=1/(√5/2)=2√5/5

ctg 2x=[(2√5/5)²-1)/2·2√5/5=(-1/5)/(4√5/5)=-√5/20