Question

The radius of a circle is estimated to be
14 inches, with a maximum error in measure-
ment of ±0.08 inches. Use differentials to
estimate the maximum error in calculating
the area of the circle using this estimate.

Answer 1

A = pi.r^2
Hence
dA = 2.pi.r.dr.

You know r and dr and hence calculate dA

Answer 2

so would it be A=2pi*r

Answer 3

dA is the maximum error in calculating the area. dr here is the error in the radius.

So plug in the values for r and dr into the equation
dA = 2.pi.r.dr
and you have dA

Answer 4

radius(r)=14
dr=0.08 or -0.08??? which one would I plug into the equation

Answer 5

Plug in both so you see the range in dA. And then you'll see you actually only needed to plug in both.

But use both at first.