Question

How to solve if sin x=0.76 what is cos x=

Answer 1

$\bf sin^2(\theta)+cos^2(\theta)=1\implies cos^2(\theta )=1-sin^2(\theta ) \\\\\\ cos(\theta )=\pm \sqrt{1-sin^2(\theta )}\\\\ -------------------------------\\\\ cos(x)=\pm \sqrt{1-sin^2(x)}\implies cos(x)=\pm \sqrt{1-(0.76)^2} \\\\\\ cos(x)=\pm \sqrt{0.4224}\implies cos(x)\approx \pm 0.64992307$