Odpowiedzi

2010-01-12T16:35:24+01:00
Sinα=4/5
sin²α+cos²α=1
cos²α=1-sin²α=1-(4/5)²=1-16/25=9/25
cosα=√(9/25)=3/5
tgα=sinα/cosα
tgα=(4/5)/(3/5)
tgα=4/3
ctgα=1/tgα=1/(4/3)=3/4