Aus Online Mathematik Brückenkurs 2

For x-values between -3 and 2, the graph of the function has a tangent which slopes downwards, i.e. negative derivative.

1.1 - Figure - Solution - The graph of f(x) in exercise 1.1:1a with interval (-3,2)

The graph of f(x) has a tangent with negative slope if -3 < x < 2.