Q. Find the average value of the function f(x)=x−58 from x=1 to x=3. Express your answer as a constant times ln2.Answer: □ln2
Set Up Integral: To find the average value of a continuous function f(x) on the interval [a,b], we use the formula for the average value of a function on an interval, which is given by:Average value = (b−a)1∫abf(x)dxHere, a=1, b=3, and f(x)=x−58.
Compute Integral: First, we need to set up the integral to calculate the average value:Average value = (1/(3−1))×∫13x−58dxThis simplifies to:Average value = (1/2)×∫13x−58dx
Evaluate Antiderivative: Now we need to compute the integral of x−58 from x=1 to x=3. This is an integral of the form ∫x−cdx, which is a natural logarithm function. The antiderivative of x−c1 is ln∣x−c∣, so the antiderivative of x−58 is 8ln∣x−5∣.
Find Average Value: We evaluate the antiderivative from x=1 to x=3:∫13x−58dx=[8ln∣x−5∣]from 1 to 3=8ln∣3−5∣−8ln∣1−5∣=8ln∣−2∣−8ln∣−4∣Since ln∣−2∣=ln(2) and ln∣−4∣=ln(4), and ln(4)=2ln(2), we have:x=30x=31x=32
Correct Error: Finally, we multiply this result by (1/2) to find the average value:Average value = (1/2)×(−8ln(2))= −4ln(2)However, we made a mistake in the sign during the evaluation of the integral. The correct evaluation should result in a positive value since we are integrating from a lower to a higher value of x, and the function (8)/(x−5) is negative on this interval. Let's correct this error.
More problems from Find the roots of factored polynomials