Question

Determinati cos x stiind ca sin x =1supra2

Answer 1

Salut,

$sin^2x+cos^2x=1,\;sau\;\left(\dfrac{1}2\right)^2+cos^2x=1,\;sau\;\dfrac{1}4+cos^2x=1,\;sau\\\\cos^2x=\dfrac{3}4\Rightarrow cosx=\pm\sqrt{\dfrac{3}4}=\pm\dfrac{\sqrt3}2.$

Green eyes.