Let f be the function defined by f(x)=3ln(x). If three subintervals of equal length are used, what is the value of the trapezoidal sum approximation for ∫23.53ln(x)dx ? Round to the nearest thousandth if necessary.Answer:
Q. Let f be the function defined by f(x)=3ln(x). If three subintervals of equal length are used, what is the value of the trapezoidal sum approximation for ∫23.53ln(x)dx ? Round to the nearest thousandth if necessary.Answer:
Rephrase Problem: Let's first rephrase the "What is the trapezoidal sum approximation for the integral of 3ln(x) from 2 to 3.5 using three subintervals of equal length?"
Divide Interval: To use the trapezoidal rule, we need to divide the interval [2,3.5] into three equal subintervals. The length of each subinterval is (3.5−2)/3=0.5.
Evaluate Function: The endpoints of the subintervals are x0=2, x1=2.5, x2=3, and x3=3.5. We will evaluate the function f(x)=3ln(x) at these points.
Apply Trapezoidal Rule: Calculate the function values: f(x0)=3ln(2), f(x1)=3ln(2.5), f(x2)=3ln(3), and f(x3)=3ln(3.5).
Substitute Values: Now, we apply the trapezoidal rule, which is given by the formula:T=(Δx/2)⋅[f(x0)+2f(x1)+2f(x2)+f(x3)],where Δx is the length of each subinterval.
Perform Calculations: Substitute the values into the trapezoidal rule formula:T=20.5×[3ln(2)+2×3ln(2.5)+2×3ln(3)+3ln(3.5)].
Calculate Sum: Perform the calculations:T=0.25×[3ln(2)+6ln(2.5)+6ln(3)+3ln(3.5)].
Add Values: Use a calculator to find the numerical values of the logarithms and perform the multiplication:T≈0.25×[3×0.6931+6×0.9163+6×1.0986+3×1.2528].
Multiply for Approximation: Calculate the sum:T≈0.25×[2.0793+5.4978+6.5916+3.7584].
Round to Nearest Thousandth: Add the values together:T≈0.25×[17.9271].
Round to Nearest Thousandth: Add the values together:T≈0.25×[17.9271].Multiply by 0.25 to get the final approximation:T≈0.25×17.9271≈4.4818.
Round to Nearest Thousandth: Add the values together:T≈0.25×[17.9271].Multiply by 0.25 to get the final approximation:T≈0.25×17.9271≈4.4818.Round to the nearest thousandth:T≈4.482.
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