Mathematics

The key is recognizing that $\sec^2 x$ is the derivative of a basic trigonometric function you've likely memorized. Rather than using integration techniques, think about which trig function, when differentiated, gives you $\sec^2 x$ back. This is a direct application of the fundamental theorem—you're reversing a differentiation rule you already know.

The key is recognizing that $\sec^2 x$ is the derivative of a basic trigonometric function you've likely memorized. Rather than using integration techniques, think about which trig function, when differentiated, gives you $\sec^2 x$ back. This is a direct application of the fundamental theorem—you're reversing a differentiation rule you already know.