# Links for 5.1, 6.3, and 6.4

Here are some helpful links for this Thursday’s and next week’s lectures:

Riemann sums left endpoint, right endpoint, midpoint

Riemann sum calculator

Solids of revolution (disk/washer method and shell method)

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### 3 Responses to Links for 5.1, 6.3, and 6.4

1. Ravanna EL says:

Professor i dont understand how to get the height in the rectangles in webwork is there a formula or something that I’m missing or those point suppose to be given?

• Kate Poirier says:

Hi Ravanna. Hopefully the email I sent helped you out, but in case anyone else has the same question…

The height of a rectangle is usually not given, but the information for finding the height of a rectangle usually is…it’s usually the value of the function for *some* point in the subinterval which forms the base of the rectangle. (We saw an example in classs where we were told to use the right-endpoints as the subintervals.) So, for example, if the big interval is [0,1] and if we’re using 10 rectangles, then the first subinterval is [0,1/10], the second subinterval is [1/10, 2/10], the third subinterval is [2/10, 3/10], and so on. If we’re instructed to use the right-endpoints of these subintervals, then the height of the first rectangle is f(1/10), the height of the second rectangle is f(2/10), the height of the third rectangle is f(3/10), and so on. Hope this helps!

2. coolal says:

can you extend the webwork?