The measurement of the radius of the end of a log is found to be 9 inches, with a possible error of 1/2 inch. Use differentials to approximate the possible propagated error in computing the area of the end of the log.

Respuesta :

Answer:

[tex]\pm 9in^2[/tex]

Step-by-step explanation:

We are given that

Radius of end of a log, r= 9 in

Error, [tex]\Delta r=\pm 1/2[/tex]in

We have to find the error in computing the area of the end of the log by using differential.

Area of end of the log, A=[tex]pi r^2[/tex]

[tex]\frac{dA}{dr}=2\pi r[/tex]

[tex]\frac{dA}{dr}=2\pi (9)=18\pi in^2[/tex]

Now,

Approximate error in area

[tex]dA=\frac{dA}{dr}(\Delta r)[/tex]

Using the values

[tex]dA=18\pi (\pm 1/2)[/tex]

[tex]\Delta A\approx dA=\pm 9in^2[/tex]

Hence, the possible propagated error in computing the area of the end of the log[tex]=\pm 9in^2[/tex]

Answer:

[tex]A = (254.34 \pm 28.26) in^2[/tex]

Step-by-step explanation:

radius, r = 9 inches

error = 0.5 inch

The area of the end is

A = 3.14 x r x r = 3.14 x 9 x 9 = 254.34 in^2

[tex]A = \pi r^2\\\\\frac{dA}{dr}=2\pi r\\dA = 2 pi r dr \\\\dA = 2 \times 3.14\times 9\times 0.5 = 28.26[/tex]

So, the area is given by

[tex]A = (254.34 \pm 28.26) in^2[/tex]