Answer
--$\int^0_\frac{-\pi}{4}(sec x)dx$
Work Step by Step
Interpreting Limits of sums as Integrals
-$\lim\limits_{||p|| \to 0}$ $\Sigma^n_{k=1} (sec c_k) Δx_k $
where P is a partition of $[\frac{-\pi}{4},0]$
as
--$\int^0_\frac{-\pi}{4}(sec x)dx$
