[an error occurred while processing this directive]
![]() |
|
|||
![]() |
![]() |
|||
[an error occurred while processing this directive] |
|
Tangents, Derivatives and DifferentiationThe DerivativeLet f(x) be a function and assume that for each value of x, we can calculate the slope of the tangent to the graph y = f(x) at x. This slope depends on the value of x that we choose, and so is itself a function. We call this function the derivative of f(x) and denote it by f ´ (x).
Hence, for a function y = f(x), we denote
Note that f(x+h) − f(x) is the change in y corresponding to the change h in x. Leibniz denoted these changes by Δy and Δx respectively. Thus For this reason, we often write. The symbol To compute the derivative of a function f(x) is to differentiate the function f with respect to x. The process of finding a derivative is called differentiation.
Example 1.For a straight line determined by y = mx + c,
the tangent of the graph (line) at each point coincides with the line.
Thus the tangent has a constant slope m. That is, Let f(x) = mx + c. Then
Example 2.We find the derivative of f(x) = x2. Hence
Exercise 1.Find the derivative of these functions using the definition of the derivative.
<< The Slope of a Tangent Line | Differentiation Index | Derivation Of The Basic Derivative Rules >>
|