The instantaneous rate of change of a function at a particular point is a measure of how the function's value changes with respect to changes in its input at that specific point. Mathematically, it is expressed as the derivative of the function. Hereβs a step-by-step explanation:
1. **Definition**:
The instantaneous rate of change of a function \( f(x) \) at a point \( x = a \) is the limit of the average rate of change of the function as the interval around \( a \) becomes infinitesimally small.
2. **Mathematical Expression**:
For a function \( f(x) \), the instantaneous rate of change at \( x = a \) is given by the derivative \( f'(a) \), which is calculated as:
\[
f'(a) = \lim_{h \to 0} \frac{f(a+h) - f(a)}{h}
\]
Here, \( h \) represents a small change in \( x \), and \( f(a+h) - f(a) \) is the change in the function's value.
3. **Derivative**:
The derivative \( f'(x) \) of a function \( f(x) \) is a function itself that provides the instantaneous rate of change of \( f \) with respect to \( x \). It is calculated as:
\[
f'(x) = \frac{d}{dx}f(x)
\]
This is obtained using various differentiation rules and techniques.
4. **Geometric Interpretation**:
The instantaneous rate of change at \( x = a \) corresponds to the slope of the tangent line to the graph of \( f(x) \) at the point \( (a, f(a)) \).
5. **Practical Application**:
In real-world terms, if \( f(t) \) represents the position of an object over time, then \( f'(t) \) gives the object's velocity at time \( t \). Similarly, in other contexts, the derivative provides the rate at which one quantity is changing with respect to another.
By finding the derivative and evaluating it at a specific point, you get the instantaneous rate of change at that point.