Question

Alguém consegue resolver?
(sec2 x - 1) . cotg x

Answer 1

$(sec^2(x)-1)*cotg(x)=\\ \left(\frac{1}{cos^2(x)}-1\right)*\frac{cos(x)}{sen(x)}=\\ \\ \left(\frac{1-cos^2(x)}{cos^2(x)}\right)*\frac{cos(x)}{sen(x)}=\\ \\ \frac{sen^2(x)}{cos^2(x)}*\frac{cos(x)}{sen(x)}=\frac{sen(x)}{cos(x)}=tg(x)$