Let f be the function defined by f(x)=x2. If four subintervals of equal length are used, what is the value of the left Riemann sum approximation for ∫12x2dx ? Round to the nearest thousandth if necessary.Answer:
Q. Let f be the function defined by f(x)=x2. If four subintervals of equal length are used, what is the value of the left Riemann sum approximation for ∫12x2dx ? Round to the nearest thousandth if necessary.Answer:
Determine Width of Subintervals: Determine the width of each subinterval. Since we are integrating from x=1 to x=2 and we are using four subintervals, the width (Δx) of each subinterval is (2−1)/4=0.25.
Identify Left Endpoints: Identify the x-values for the left endpoints of each subinterval.The left endpoints for the subintervals are x=1, x=1.25, x=1.5, and x=1.75.
Evaluate Function Values: Evaluate the function f(x)=x2 at each of the left endpoints.f(1)=12=1f(1.25)=1.252=1.5625f(1.5)=1.52=2.25f(1.75)=1.752=3.0625
Calculate Rectangle Areas: Multiply each function value by the width of the subintervals to find the area of each rectangle.Area1 = f(1)×Δx=1×0.25=0.25Area2 = f(1.25)×Δx=1.5625×0.25=0.390625Area3 = f(1.5)×Δx=2.25×0.25=0.5625Area4 = f(1.75)×Δx=3.0625×0.25=0.765625
Sum Rectangle Areas: Sum the areas of the rectangles to find the left Riemann sum approximation. Left Riemann Sum = Area1+Area2+Area3+Area4=0.25+0.390625+0.5625+0.765625
Calculate Total Sum: Calculate the total sum to find the approximation.Left Riemann Sum = 0.25+0.390625+0.5625+0.765625=1.96875
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