# Calculate M4

• Mar 29th 2010, 08:00 PM
tbenne3
Calculate M4
• Mar 29th 2010, 08:10 PM
mr fantastic
Quote:

Originally Posted by tbenne3

What is \$\displaystyle M_4\$ meant to mean? MIdpoint Rule using 4 rectangles?

Please remember that notation that is obvious to you the person wanting help is not always obvious to us the people you want help from.
• Mar 29th 2010, 08:15 PM
tbenne3
Quote:

Originally Posted by mr fantastic
What is \$\displaystyle M_4\$ meant to mean? MIdpoint Rule using 4 rectangles?

Please remember that notation that is obvious to you the person wanting help is not always obvious to us the people you want help from.

Sorry about that, it stands for Midpoint Approximation (Mn)
• Mar 29th 2010, 08:16 PM
mr fantastic
Quote:

Originally Posted by tbenne3
Sorry about that, it stands for Midpoint Approximation (Mn)

OK, so your textbook and class notes will have a formula and examples. Where are you stuck here?
• Mar 29th 2010, 08:22 PM
tbenne3
Quote:

Originally Posted by mr fantastic
OK, so your textbook and class notes will have a formula and examples. Where are you stuck here?

Ok well in the text they have a similar problem to look at and it has
f(x)=x^2, [0,1]

and their solution is

(1/4)(.125^2+.375^2+.625^2+.875^2)

I cant figure out where they are getting the .125,.375,.625,.875
• Mar 29th 2010, 08:44 PM
drumist
Quote:

Originally Posted by tbenne3
Ok well in the text they have a similar problem to look at and it has
f(x)=x^2, [0,1]

and their solution is

(1/4)(.125^2+.375^2+.625^2+.875^2)

I cant figure out where they are getting the .125,.375,.625,.875

In that example, they are dividing the interval [0,1] into 4 equal sub-intervals, like so:

[0,0.25] [0.25,0.5] [0.5,0.75] and [0.75,1]

Next, you need to find the midpoint of each interval, because this is what you will use to plug into f(x) for each sub-interval.

Midpoint of [0,0.25] is 0.125
Midpoint of [0.25,0.5] is 0.375
etc.