Let f(x)=8−2x and g(x)=x3−7x2+12x. Find the sum of the areas enclosed by the graphs of f and g between x=1 and x=4.Use a graphing calculator and round your answer to three decimal places.
Q. Let f(x)=8−2x and g(x)=x3−7x2+12x. Find the sum of the areas enclosed by the graphs of f and g between x=1 and x=4.Use a graphing calculator and round your answer to three decimal places.
Understand the problem: Understand the problem.We need to find the area between the curves of f(x) and g(x) from x=1 to x=4. This is equivalent to integrating the absolute value of the difference between f(x) and g(x) over the interval [1,4].
Set up the integral: Set up the integral to find the area between the curves.The area A between the curves is given by the integral from x=1 to x=4 of the absolute value of the difference between f(x) and g(x), which is ∣f(x)−g(x)∣. So, we have:A=∫14∣f(x)−g(x)∣dx
Calculate f(x)−g(x): Calculate f(x)−g(x). Before we can integrate, we need to find the expression for f(x)−g(x): f(x)−g(x)=(8−2x)−(x3−7x2+12x)=−x3+7x2−14x+8
Determine points of intersection: Determine the points of intersection between f(x) and g(x). To find the points of intersection, we set f(x)=g(x): 8−2x=x3−7x2+12x0=x3−7x2+14x−8 We can use a graphing calculator to find the points of intersection within the interval [1,4].
Use graphing calculator: Use a graphing calculator to find the points of intersection.After plotting the functions on a graphing calculator, we find that the functions intersect at x=1 and x=4. Since these are the limits of our integral, we do not need to split the integral into multiple parts.
Integrate to find area: Integrate the function to find the area.We can now integrate the function from x=1 to x=4. Since we are looking for the area, we take the absolute value of the function:A=∫14∣−x3+7x2−14x+8∣dxWe can use a graphing calculator to evaluate this integral.
Evaluate integral: Evaluate the integral using a graphing calculator.Using the graphing calculator, we find the integral from x=1 to x=4 of ∣−x3+7x2−14x+8∣ dx to be approximately 18.667.