If f′ (x) > 0 in a certain interval, what does show about f(x)?

Increasing and decreasing both

Decreasing function

Increasing function

None of these

If $f'(x) > 0$ in an interval, it means the function $f(x)$ is increasing in that interval.

A positive derivative indicates that the function's slope is positive, meaning it moves upward as $x$ increases.