### Home > CALC > Chapter 8 > Lesson 8.1.4 > Problem8-43

8-43.

Quotient Rule.

$\frac{d}{dx}\text{sec}x=\text{sec}x\text{tan}x$

$=\frac{2x^{3}\text{cos}(2x)-3x^{2}\text{sin}(2x)}{x^{6}}$

We know that k is a variable (not a constant) because it appears in the

$\frac{d}{dk}.$

Product Rule.