Recent content by lilly92

  1. L

    Summation Question: Substituting y=ai+b in c=Σ(i2*yi)?

    Okay I understand that, thank you. But what if I want to test with polynomials of second degree or higher? My y data can be manually changed and c takes a specific value. What I'm trying to do is figure out which ys to change to make c take that value and/or by how much. Is that possible?
  2. L

    Summation Question: Substituting y=ai+b in c=Σ(i2*yi)?

    I don't care about the exact approximation because I test various polynomials to figure out for which c approximates a specific known value. But my problem is what to do about the coefficients of the polynomials. Is there a way to calculate them in order to calculate c?
  3. L

    Summation Question: Substituting y=ai+b in c=Σ(i2*yi)?

    Homework Statement I have a set of data (i, yi). A polynomial fit of 1st degree would be y=ai+b, right? If I have c=Σ(i2*yi) is it correct to substitute y=ai+b inside the summation? Homework Equations The Attempt at a Solution
  4. L

    Solve Summation Problem: Const=b*∑i2yi+∑f(I)f(y)...

    Yes, that's what I mean. I apologise.I didn't think the exact equation was necessary because I'm looking for some general pointers or even a yes-or-no answer if what I'm trying to do can be done. Thank you for your time.
  5. L

    Solve Summation Problem: Const=b*∑i2yi+∑f(I)f(y)...

    clarification OK let me try and explain it a little better. I know that const takes a specific value, i.e. const=0.05. I need to find what the "arrangement" of yis must be for this to happen. Think of it as follows: If y are a set of data values in what order should these values appear for the...
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    Solve Summation Problem: Const=b*∑i2yi+∑f(I)f(y)...

    Homework Statement I have an equation in the general form: const=b*∑i2yi+∑f(I)f(y)...) where const,b are known constants.I have a general question.Is it possible from equations like this to identify how the ys should be distributes so as the const takes a specific value, e.g const=0.05? What...
  7. L

    Solve for a variable inside a summation

    I need to solve the equation for x, where a is a known constant and . The bs are known too. What i need to do is sto find for which xs I'll have a specific value of a, eg a=0.5, i.e. solve for x and substitute the a. I believe that the result will be a group of xs and not a single...
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