Question

Найдите cos β, tg β и ctg β, если sin β 4/5

Answer 1

Cos²β=1 - sin²β
cosβ=√1-16/25=√9/25=3/5
tgβ=√(1-cos²β)/cosβ=√(1-9/25)/(3/5)=√16/25*5/3=4/√15=(4√15)/15
ctgβ=1/tgβ=√15/4