Question

4(1-sen^2).(sec^2-1)=3

Answer 1

Lembre-se que:

$\boxed{1-sen^2x=cos^2x}\\ \\ \boxed{sec^2x=\frac{1}{cos^2x}}$

$4cos^2x*(\frac{1}{cos^2x}-1)=3\\ \\ cos^2x*(\frac{1}{cos^2x}-1)=\frac{3}{4}\\ \\ 1-cos^2x=\frac{3}{4}\\ \\ sen^2x=\frac{3}{4}\\ \\ senx=\frac{\sqrt3}{2} \Rightarrow x=\frac{\pi}{3} \ rad =60^o$