4.8 - Differentials. Linear (or Tangent Line) Approximations. For values close to a , . Linear Approximation – Examples. Determine the linearization (another name for linear approximation) of f ( x ) = ln x at a = 1. Find the linear approximation of the function .
4.8 - Differentials
Linear (or Tangent Line) Approximations
For values close to a,
Linear Approximation – Examples
Determine the linearization (another name for linear approximation) of f (x) = ln x at a = 1.
Find the linear approximation of the function
And use it to approximate the numbers
Up to now, we’ve thought of dy/dx as notation for a derivative. We can think of dx and dy as separate quantities called differentials.
We can now think of dy/ dx as a ratio of two quantities (the differential of y and the differential of x). So for a given change in x (dx) we can calculate a change in y (dy).
Differentials – Example 1
Find the differential dy and evaluate dy for the given values of x and dx.
Differentials – Example 2
You may have used this concept when calculating errors in measurements or calculations.
The radius of a circular disk is given as 24 cm with a maximum error in measurement of 0.2 cm. (a) Use differentials to estimate the maximum error in the calculated area of the disk. (b) What is the relative errors (dA / A)