16 September, 19:35

The circumference of a sphere was measured to be 72 cm with a possible error of 0.5 cm. (a) Use differentials to estimate the maximum error in the calculated surface area. (Round your answer to the nearest integer.) 22.91 Correct: Your answer is correct. cm2 What is the relative error

+5
1. 16 September, 21:47
0
dA (s) = 22,917 cm² maximum error

dA (s) / A (s) = 0,01389 or 1,38 % relative error

Step-by-step explanation:

The Volume of a sphere is:

V (s) = 4/3) * π*r³ where r is the radius of circumference

If the length of circumference is 72 cm then

L (c) = 72 = 2*π*r

r = 72/2*π

r = 72 / 6,28 ⇒ r = 11,46 cm

And

L (c) = 2*π*r

Differentiation on both sides of the equation give:

dL (c) = 2*π*dr

dr = dL (c) / 2*π

dr = 0,5 / 6,28 ⇒ dr = 0,07961

The surface area Is:

A (s) = 4*π*r²

And the maximum or absolute error is

dA (s) = 8*π*r*dr

dA (s) = 22,917 cm²

The relative error is dA (s) / A (s)

dA (s) / A (s) = 8*π*r*dr / 4*π*r²

dA (s) / A (s) = 2 * (0,07961) / (11,46)

dA (s) / A (s) = 0,01389 or 1,38 %