## Calculus (3rd Edition)

$f'(5.5)$
The slope of the tangent line at x=5.5 in the given figure will be greater than the slope of the tangent line at x=6.5. Since the derivative at a point is defined as the slope of the tangent line at that point, thus $f'(5.5)$ will be greater than $f'(6.5)$.