KS Connected Rate of Change The chain rule can be used to solve problem involving rates of change....

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KS Connected Rate of Change The chain rule can be used to solve problem involving rates of change. Example 1 The length of the side of a square is increasing at a constant rate of 1.5 cm/s. At the moment when the length is of the side is 10 cm, find the rate of the increase of the area. Given 1.5, require dl dr dt dt 2 2 dA A l l dl The chain rule: 2 1.5 2 10 1.5 dA dA dl l dt dl dt 2 1 30cm s

Transcript of KS Connected Rate of Change The chain rule can be used to solve problem involving rates of change....

Page 1: KS Connected Rate of Change The chain rule can be used to solve problem involving rates of change. Example 1 The length of the side of a square is increasing.

KS

Connected Rate of Change

The chain rule can be used to solve problem involving rates of change.

Example 1The length of the side of a square is increasing at a constant rate of 1.5 cm/s. At the moment when the length is of the side is 10 cm, find the rate of the increase of the area.

Given 1.5, requiredl dr

dt dt 2 2

dAA l l

dl

The chain rule: 2 1.5 2 10 1.5dA dA dl

ldt dl dt

2 130cm s

Page 2: KS Connected Rate of Change The chain rule can be used to solve problem involving rates of change. Example 1 The length of the side of a square is increasing.

KS

Connected Rate of Change

Example 2The length of the edge of a cube is increasing at a constant rate of 4.2 mm s-1. At the moment when the length of the edge is 50 mm, find the rate of increase of the volume.

Given 4.2, requiredl dv

dt dt 3 23

dVV l l

dl

The chain rule: 2 23 4.2 3 50 4.2dV dV dl

ldt dl dt

3 131500mm s

3 131.5cm s

Page 3: KS Connected Rate of Change The chain rule can be used to solve problem involving rates of change. Example 1 The length of the side of a square is increasing.

KS

Connected Rate of Change

Example 3The area of a circle is decreasing at a rate of 1.4 cm2 s-1. Find the rate of change of the circumference when the radius is 5cm.

Given 1.4, requiredA dC

dt dt 2 2

dAA r r

dr

The chain rule: 1 141.4

2 5 100

dr dr dA

dt dA dt

10.28cms

142

100

dC dC dr

dt dr dt