Q. What is the average value of 3x2+4x on the interval 2≤x≤6 ?
Average Value Formula: To find the average value of a function f(x) over the interval [a,b], we use the formula:Average value = (b−a)1∫abf(x)dxHere, f(x)=3x2+4x, a=2, and b=6.
Definite Integral Calculation: First, we need to find the definite integral of f(x) from 2 to 6.∫26(3x2+4x)dxThis requires us to integrate the function term by term.
Term by Term Integration: The integral of 3x2 with respect to x is x3, and the integral of 4x with respect to x is 2x2. So, ∫ of (3x2+4x)dx=x3+2x2.
Evaluation at Limits: Now we evaluate the antiderivative at the upper and lower limits of the interval and subtract: 63+2⋅62 - 23+2⋅22
Upper Limit Calculation: Calculating the values:(63+2×62)=(216+2×36)=(216+72)=288(23+2×22)=(8+2×4)=(8+8)=16
Subtract Lower Limit: Subtract the lower limit evaluation from the upper limit evaluation: 288−16=272
Average Value Calculation: Now, we divide this result by (b−a) to find the average value:Average value = (6−2)272
Denominator Calculation: Calculating the denominator: 6−2=4
Division Result: Dividing the result by the interval length:Average value = 4272
Final Average Value: Simplifying the fraction:Average value = 68