Estimate the area under the graph of f(x)=x^2+3x from x=1 to x=7 using 3 approximating rectangles and left endpoints

Answer 1

Δx = (7-1)/3 = 2. The points are x = 1,3,5,7 and the rectangles have a base of 2

The heights of the rectangles is the left hand value of f(x) for each rectangle

Add up Δx*f(x_i) where i is the 1st, 2nd, 3rd values of x

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