Let f be the function defined by f(x)=3x. If three subintervals of equal length are used, what is the value of the trapezoidal sum approximation for ∫033xdx ? Round to the nearest thousandth if necessary.Answer:
Q. Let f be the function defined by f(x)=3x. If three subintervals of equal length are used, what is the value of the trapezoidal sum approximation for ∫033xdx ? Round to the nearest thousandth if necessary.Answer:
Understand trapezoidal rule: Understand the trapezoidal rule and set up the problem.The trapezoidal rule is a numerical method to approximate the definite integral of a function. It works by dividing the interval of integration into smaller subintervals, then approximating the area under the curve for each subinterval by the area of a trapezoid. The formula for the trapezoidal rule with n subintervals is:T=(Δx/2)⋅(f(x0)+2f(x1)+2f(x2)+…+2f(xn−1)+f(xn))where Δx is the width of each subinterval, and x0,x1,…,xn are the endpoints of the subintervals.In this case, we are using three subintervals to approximate the integral from 0 to 3, so Δx=(3−0)/3=1.
Calculate function values: Calculate the function values at the endpoints of the subintervals.We need to evaluate the function f(x)=3x at the endpoints of the subintervals, which are x=0, x=1, x=2, and x=3.f(0)=30=1f(1)=31=3f(2)=32=9f(3)=33=27
Apply trapezoidal rule: Apply the trapezoidal rule to approximate the integral.Using the trapezoidal rule formula:T=(Δx/2)⋅(f(0)+2f(1)+2f(2)+f(3))T=(1/2)⋅(1+2⋅3+2⋅9+27)T=(1/2)⋅(1+6+18+27)T=(1/2)⋅52T=26
Round result: Round the result to the nearest thousandth if necessary.Since the result is an integer, there is no need to round it. The value of the trapezoidal sum approximation is 26.
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