If f(x) represents a quantity, then the derivative of the quantity is the instantaneous slope of that quantity.
- Therefore, just by knowing the sign of the derivative, we then know whether the slope is increasing, decreasing, or constant on that interval.

<aside> 💡 Remember that the slope is indicted by $\frac {\Delta y} {\Delta x}$

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The secant line and tangent line definition of derivative, indicts that the unit of the derivative is y axis unit over the x axis unit.

Sub-Unit