Sinx= 4/5 π/2 <x<π найти cos, tan, cot

Question

Sinx= 4/5

π/2

найти cos, tan, cot

Answer 1

Sin^2x+cos^2x=1
cos^2x=1-sin^2x
cos^2x=1-(4/5)^2=1-16/25=9/25
cosx=√9/25=3/5

tgx =sinx/cosx
tgx=4/5:3/5=4/3

ctgx=cosx/sinx
ctgx=3/5:4/5=3/4