Question

найдите ctga, sina и tga, если: 1) cosa=513, cosa=1517, 3)cosa=0,6

Answer 1

sin a = $sqrt{1-cos ^{2} a} = sqrt{1- frac{5}{13} ^{2}}= frac{12}{13}$
tg a = sin a / cos a = 12/13 / 5/13 = 12/5
ctg a = 1 / tg a = 5/12