Question

Seja x um ângulo tal que sen² x - cos² x = 1/2. Então, quanto vale tg² x?

Answer 1

$sen^2x-cos^2x=\frac{1}{2} \\\\cos2x=0,5\\\\cos^{-1} 0,5=2x\\\\60=2x\\\\x=30\\\\--------------------------\\\\tg^2x=tg^230=0,3333...=\frac{1}{3}$