Average rate of change

[Preeti]

A child who weighs 34 kg is seated on a seesaw, while a child who weighs 40kg is
situated on the opposite end of the seesaw. The function D(x) = 34(x)/40 gives the
distance that the 40 kg child must sit from the center of the seesaw when the 34 kg
child sits x meters from the center. The seesaw is 9m long. Find the average rate of
change in distance as the lighter child’s distance changes from 1.5m to 2.5m, and
find the instantaneous rate of change at 2.5m.

 

[fasteddie65]

A child who weighs 34 kg is seated on a seesaw, while a child who weighs 40kg is
situated on the opposite end of the seesaw. The function D(x) = 34(x)/40 gives the
distance that the 40 kg child must sit from the center of the seesaw when the 34 kg
child sits x meters from the center. The seesaw is 9m long. Find the average rate of
change in distance as the lighter child’s distance changes from 1.5m to 2.5m, and
find the instantaneous rate of change at 2.5m.

Finding the average rate of change is like finding the slope of the secant line. Use the slope formula with (1.5, D(1.5)) and (2.5, D(2.5)) as the two points.

The instantaneous rate of change is simply the derivative at 2.5.

 

[Preeti]

Thank you, i didnt know if i had to include the lenght of the see saw or not