Question

найти sin a, tg a, ctg a, если cos a =-1/3, п/2

Answer 1

sina=√(1-cos²a)=√(1-1/9)=√(8/9)=2√2/3
tga=sina/cosa=2√2/3:(-1/3)=-2√2/3*3=-2√2
ctga=1/tga=1/2√2=√2/4