Question

Calculati cosx stiind ca sinx = 1/3 , iar x ∈ ($\pi /2$ , $\pi$)

Answer 1

(sinx)^2+(cosx)^2=1  =>cosx=√(1-(sinx)^2=√(1-1/9)=√8/9=2√2/3
cosx=2√2/3