Chapter 5 - Section 5.3 - The Fundamental Theorem of Calculus - 5.3 Exercises - Page 400: 50

$\int_{1}^{6} x^{-4}~dx = \frac{215}{648}$

We can find the area under the graph: $\int_{1}^{6} x^{-4}~dx$ $=-\frac{1}{3}x^{-3}~\vert_{1}^{6}$ $=-\frac{1}{3}(\frac{1}{6^3} -\frac{1}{1^3})$ $=-\frac{1}{3}(\frac{1}{216} -1)$ $=-\frac{1}{3}(-\frac{215}{216})$ $=\frac{215}{648}$