sin²α+cos²α = 1
sin²α+ (12/13)²α = 1
sin²α + 144/169 α =1
sin²α = 1- (144/169)
sin²α=25/169
sinα=√25/169 (cały ułamek jest pod √)
sinα=5/13
tgα=sinα/cosα
tgα=5/13 : 12/13 = 5/13 * 13/12 = 5/12
ctgα=cosα/sinα
ctgα=12/13 : 5/13 = 12/13 * 13/5 = 12/5 = 2,5
