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SFares14-Alexandrite
14-Alexandrite
May 28, 2014
Solved

Find function, root function

  • May 28, 2014
  • 2 replies
  • 2143 views

Hello,

in the attached sheet, please scroll down to the red arrow. When i used the Find function, i can find the root, but when i try to do it with the "root" function i get an error. if i change the guess value to .0001, i will get an answer. But this answer is incorrect because the correct answer is what you get with the Find function which is .0021273. The reason why i am using the root function so i can assign the answer to a variable. I tried to assign the Find function value to a variable, it does not let me unless i dont know how to do it. Is there a better and accurate way to do this w/o worrying about convergence? Thanks!

Best answer by Fred_Kohlhepp

You can assign a variable from Find.

2 replies

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Fred_Kohlhepp23-Emerald IAnswer
23-Emerald I
May 28, 2014

You can assign a variable from Find.

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SFares14-AlexandriteAuthor
14-Alexandrite
May 28, 2014

Thank you Fred!

in the masonry part i tried to assign a variable to find function as you did for the steel section, but it did not work for me. Please scroll down to the blue arrow. what am i doing wrong?

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Fred_Kohlhepp23-Emerald I
23-Emerald I
May 28, 2014

You can have only one Find for each given, you've got two. Disable or eliminate the Find(r) = and the second one will work.

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Werner_E25-Diamond I
25-Diamond I
May 28, 2014

There is a typo in the definition of f(rho). You typed "2*M" instead of "n*M" in the first denominator.

As you found out yourself a closer guess value makes the root function work as well and because of the typo, both solutions are correct ;-).

You may also use the root() function without any guess value

28.05.png

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SFares14-AlexandriteAuthor
14-Alexandrite
May 28, 2014

Good catch.Thank you Werner!

i did not know that i can use the root function w/o guess value. what do the highlited numbers represent? Thanks!

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Werner_E25-Diamond I
25-Diamond I
May 28, 2014

i did not know that i can use the root function w/o guess value. what do the highlited numbers represent? Thanks!

Why don't you look it up in the help? They are the limits of the interval the solution is searched in.

BTW, you can't use Find() twice at the end of a solve block, the second will throw an error as to the missing "given".

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