A function f(x) is INCREASING on an interval if for all x in the interval:
- $f''(x) > 0$ (positive second derivative)
- $f'(x) < 0$ (negative first derivative)
- $f'(x) > 0$ (positive first derivative)
- $f(x) > 0$ (positive function value)
Show answer and solution
Correct answer: C. $f'(x) > 0$ (positive first derivative)
f is INCREASING on an interval if f'(x) > 0 there.
f''(x) > 0 means concave up (different concept).
f' < 0 means decreasing.