Question

Sin a и ctg a,если cos a = 0.8 и 0

Answer 1

1) cos a=0.8
    sin a=$sqrt{1-cos^{2} alpha }$=$sqrt{1-0.64} = sqrt{0.36} =0.6$
    ctg a=$frac{cos alpha }{sin alpha } = frac{0.8}{0.6} = frac{4}{5} * frac{5}{3} = frac{4}{3} =1 frac{1}{3}$

2)cos a=0
   sin a=$sqrt{1-0} =1$
   ctg a=$frac{0}{1} =0$