A derivative $f^{\prime }$ of a function $f$ is a value that describes how fast $f$ is growing or decreasing.

• If $f^{\prime }$ is positive at point c, then $f$ is growing on that point c
• If $f^{\prime }$ is negative at point c, then $f$ is decreasing on that point c
• If $f^{\prime }$ is 0 at point c, then $f$ is on Local Minima or Global Minima