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MarineBeanpole1-Visitor
1-Visitor
March 24, 2022
Solved

Trouble Using Trapezoidal Rule to Calculate Total Areas

  • March 24, 2022
  • 1 reply
  • 2332 views

I am struggling to get MathCAD Prime 7.0 to multiply two sets of data in order to find a total area. I know that the solution should be simple, but I cannot find the right way to go about getting the program to output the desired information without running into an error. 

 

The question that I am attempting to solve is attached and so is the PDF of my current workings on MathCAD.

 

Any help or pointers would be greatly appreciated!

Best answer by Werner_E

Additionally to pictures and pdfs you should always attach your worksheet as well!

You should x define as  a vector, not a range. Then you should vectorize the function call f(x) to be on the save side even though it would not be necessary given your function is x^4.

Furthermore your approach ignores the fact that the lower integral limit is a=15 and not zero!

 

After correcting those errors it may look like this (done in MC15)

Werner_E_0-1648143705944.png

You can get rid of the vector "Multiplier" by using

Werner_E_2-1648144367334.png

 

But you may consider to write a utility function "trapezoid" to do the job so you can compare the results with different numbers for the ordinates easily

Werner_E_1-1648143772047.png

 

 

1 reply

W
Werner_E25-Diamond IAnswer
25-Diamond I
March 24, 2022

Additionally to pictures and pdfs you should always attach your worksheet as well!

You should x define as  a vector, not a range. Then you should vectorize the function call f(x) to be on the save side even though it would not be necessary given your function is x^4.

Furthermore your approach ignores the fact that the lower integral limit is a=15 and not zero!

 

After correcting those errors it may look like this (done in MC15)

Werner_E_0-1648143705944.png

You can get rid of the vector "Multiplier" by using

Werner_E_2-1648144367334.png

 

But you may consider to write a utility function "trapezoid" to do the job so you can compare the results with different numbers for the ordinates easily

Werner_E_1-1648143772047.png

 

 

    M
    MarineBeanpole1-VisitorAuthor
    1-Visitor
    March 25, 2022

    Thanks very much for your help Werner_E!

    I've attached the .mcdx sheet that I was originally working with, but I will definitely use your input above and attempt to rectify my errors.

     

    Thank you for your help.

    W
    Werner_E25-Diamond I
    25-Diamond I
    March 25, 2022

    Fine, feel free to ask again if something still is unclear

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