1. Approximating Change www.mathxtc.com

2. Goto Calculus-Help.comCalculus-Help.com Revision: Differentiation by First Principles

3. Example: Consider a circle of radius 10 cm. If the radius increases by 0.1 cm, approximately how much will the area change? very small change in A very small change in r (approximate change in area)

4. Compare to actual change: New area: Old area:

5. Example: If V=2x 3 use differentiation to find the approximate percentage change in V when x changes by 2% very small change in V very small change in x (when x changes by 2%, V changes by 6%)

6. Example: If V=2x 3 use differentiation to find the approximate percentage change in V when x changes by 2% (when x changes by 2%, V changes by 6%) A different method !!