Finding Lower Sums for a Region

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In summary, to find the lower sum for the region bounded by f(x) = 25 - x^2 and the x-axis between x = 0 and x = 5, you need to use the formula ΔX = b-a/n and find the left endpoints. This can be done by using the formula mi = 5(i-1)/n. After using sigma notation and algebra, you will end up with the solution 125/n^3 {(n(n+1)(2n+1)/6) - 2[n(n+1)/2] + n}.
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Homework Statement



FIND THE LOWER SUM FOR THE REGION BOUNDED BY f(x) = 25 - x^2 AND THE X - AXIS BETWEEN x = 0 and x = 5. SOLVE ANALYTICALLY!

Homework Equations



None that I'm aware of...

The Attempt at a Solution



f(x) = -x2 + 25
and
[tex]\Delta[/tex]X = b-a/n = 5-0/n = 5/n



Here's my question: how do I find the left endpoints in order to solve for the lower sum?
 
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Okay, here's what I have thus far, and I'm not sure this is correct:


mi= 5(i-1)/n

After much sigma notation and algebra...

eventually ending up with 125/n3 {(n(n+1)(2n+1)/6) - 2[n(n+1)/2] + n}
 

FAQ: Finding Lower Sums for a Region

What is a lower sum for a region?

A lower sum for a region is a method used in calculus to approximate the area under a curve by dividing the region into smaller rectangles and finding the sum of the areas of the rectangles.

How do you find a lower sum for a region?

To find a lower sum for a region, you need to first divide the region into smaller rectangles of equal width. Then, find the height of each rectangle by taking the minimum value of the function within that rectangle. Finally, add the areas of all the rectangles to get the lower sum for the region.

Why is finding lower sums important?

Finding lower sums is important because it allows us to approximate the area under a curve, which is a fundamental concept in calculus. It also helps us to better understand the behavior of functions and make predictions based on the data.

What are the applications of finding lower sums?

Finding lower sums has many applications in fields such as physics, engineering, and economics. It is used to calculate work, displacement, and other physical quantities in physics, and to estimate the cost of production and demand for goods in economics.

What are the limitations of using lower sums?

Using lower sums to approximate the area under a curve is not always accurate, as it relies on dividing the region into smaller rectangles and taking the minimum value of the function within each rectangle. This method can also be time-consuming and may not provide an exact solution. Other methods, such as using upper sums or the trapezoidal rule, may provide better approximations.

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