Let f be the function defined by f(x)=4x. If four subintervals of equal length are used, what is the value of the midpoint Riemann sum approximation for ∫284xdx ? Round to the nearest thousandth if necessary.Answer:
Q. Let f be the function defined by f(x)=4x. If four subintervals of equal length are used, what is the value of the midpoint Riemann sum approximation for ∫284xdx ? Round to the nearest thousandth if necessary.Answer:
Calculate Subinterval Length: To calculate the midpoint Riemann sum, we first need to determine the length of each subinterval. The interval [2,8] has a length of 8−2=6. Since we are using four subintervals, each subinterval will have a length of 6/4=1.5.
Find Midpoints of Subintervals: Next, we need to find the midpoints of each subinterval. The subintervals are [2,3.5], [3.5,5], [5,6.5], and [6.5,8]. The midpoints of these subintervals are 2.75, 4.25, 5.75, and 7.25, respectively.
Evaluate Function at Midpoints: Now we evaluate the function f(x)=4x at each midpoint. This gives us the values f(2.75), f(4.25), f(5.75), and f(7.25). We calculate these values as follows:f(2.75)=42.75f(4.25)=44.25f(5.75)=45.75f(7.25)=47.25
Perform Function Value Calculations: We perform the calculations for each function value:f(2.75)=42.75≈4×1.658≈6.632f(4.25)=44.25≈4×2.062≈8.248f(5.75)=45.75≈4×2.397≈9.588f(7.25)=47.25≈4×2.692≈10.768
Calculate Midpoint Riemann Sum: The midpoint Riemann sum is the sum of the function values at the midpoints multiplied by the length of each subinterval. So, we have:Midpoint Riemann Sum = (f(2.75)+f(4.25)+f(5.75)+f(7.25))×length of subintervalMidpoint Riemann Sum ≈(6.632+8.248+9.588+10.768)×1.5
Calculate Sum of Function Values: We calculate the sum of the function values and then multiply by the length of the subinterval:Midpoint Riemann Sum ≈(6.632+8.248+9.588+10.768)×1.5Midpoint Riemann Sum ≈35.236×1.5Midpoint Riemann Sum ≈52.854
Round Result to Nearest Thousandth: We round the result to the nearest thousandth as requested:Midpoint Riemann Sum ≈52.854 (rounded to three decimal places)
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