
Doug C. answered 06/25/20
Math Tutor with Reputation to make difficult concepts understandable
The width of each sub-interval will be (3-0)/6 or w=1/2.
The list of xi will start at right hand end point of first sub-interval, i.e. 1/2 then increase by 1/2 for the next right hand endpoint.
x1=1/2
x2=1/2 + 1/2 = 1
x3=1/2 + 2(1/2) = 3/2
x4=1/2 + 3(1/2) = 4/2 = 2
x5= 1/2 + 4(1/2) = 5/2
x6= 1/2 + 5(1/2) = 6/2 = 3
The height of each rectangle will be (xi)3.
The area of the ith rectangle will be (xi)3w.
So R1 has an area = (1/2)3(2)
R2 has an area (1)3(2)
And so on.
Add up the areas of the 6 rectangles and you will have an approximation to the area.
Try visiting this graph to see the result.:
desmos.com/calculator/fthc1f9d8o