We are familiarwith the formulasfor Perimeterand Area:
Supposewe knowthat at an instantof time,the lengthis changingat the rate of ft/hourand the perimeter
is changingat a rate of ft/hour. At whatrate is the widthchangingat that instant?
Solution:
If we differentiatethe originalequation,we have
Equation2:
Substitutingour knowninformationinto EquationII, we have
The widthis changingat a rate of ft/hour.
Okay, ratherthan providinga relatedratesprobleminvolvingthe area of a rectangle,we will leaveit to you
to makeup and solvesucha problemas part of the homework(HW #1).
Let’s look at one moregeometricmeasurementformula.
Example3:Volumeof a RightCircularCone