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Homework Help: Help with a simultaneous equation!

  1. Aug 24, 2011 #1
    Hi guys,

    I was trying to solve this:


    These were my answers: L = 1.293916796 M = 0.253577206

    I tried to get a math software to solve them so I could check my answer but I just couldn't... Can anyone check whether they get the same answers as I do?

    Peter G.
  2. jcsd
  3. Aug 24, 2011 #2


    Staff: Mentor

    You should be able to check them using just a calculator. It might be helpful to rearrange your equations a little, though, and storing one or both of your values for L and M in the memory would be helpful.

    830.7(1+Le-4M)= 1220.5
    609(1+Le-M) = 1220.5

    Just calculate the values of the expressions on the left sides, above. You should get 1220.5 or something close to it.
  4. Aug 24, 2011 #3

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    What is stopping you from substituting your L and M values into the equations to check if they work?

    Anyway, in this case you could set L*exp(-M) = x and exp(-3M) = y. The second equation reads as 1220.5 = 609*(1+x), so you can get x. The second reads as 1220.5=830.7*(1+x*y), so knowing x you can get y. Now you can get M and L.

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