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Chapter 5 Integral. Estimating with Finite Sums. Approach . Approach (2). Both approach are called Upper sum because they are obtained by taking the height of each rectangle as the maximum (uppermost) value of ƒ(x) for x a point in the base interval of the rectangle.
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Both approach are called Upper sum because they are obtained by taking the height of each rectangle as the maximum (uppermost) value of ƒ(x) for x a point in the base interval of the rectangle. • Now, we will be using what so called lower sum
Distance travelled • Suppose we know the velocity function y(t) of a car moving down a highway, without changing direction, and want to know how far it traveled between times t=a and t=b • If we already known an antiderivative F(t) of v(t) we can find the car’s position function s(t) by setting s(t)=F(t)+C. • The travelled distance is s(b)-s(a) • How to calculate in case we have no formula s(t)? • We need an approach in calculating s(t)
approach • Subdivide the interval [a, b] into short time intervals on each of which the velocity is considered to be fairly constant. • distance = velocity x time • Total distance
Limits of Finite Sums Solution: We start by subdividing [0, 1] into n equal width subintervals The lower sum of rectangular is :
Riemann Sums(2) the width of the kth subinterval is
Riemann Sums (4) Among three figures, which one gives us the most accurate calculation?
Riemann Sums (5) • In previous calculation, we can improve accuracy by increasing number of interval (n). • However, in Reimann sum, we can go to more accurate calculation by making |P| goes to zero • We define the norm of a partition P, written |P| to be the largest of all the subinterval widths. If |P| is a small number, then all of the subintervals in the partition P have a small width.
The Fundamental Theorem of Calculus (2) But remember this