Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Exponential problem

  1. Jun 27, 2005 #1
    i have an exponential problem that i could not solve.
    [tex] (b-a-2)e^b + (b-a)e^a [/tex] where a and b are constant. Is it the same as [tex] b^2 -2e^b + 6b - a^2 + 2e^a - 6a [/tex] ?
    Hope that someone kind could spend some time helping me and list down the steps for me. If they are not equal can you pls tell me too?

    Thank you!
  2. jcsd
  3. Jun 27, 2005 #2
    They aren't equal. Not sure what you are doing,
    [tex] (b-a-2)e^b + (b-a)e^a [/tex]

    Just use regular old distribution,

    [tex] (a+b+c+d)x = ax + bx + cx + dx [/tex]

    You shouldnt end up with anything squared, and everything should have an exponential attached to it.
  4. Jun 28, 2005 #3
    sure, easy. if b=a=0 then the left side left gives you -2 and the right side gives you 0.
  5. Jun 28, 2005 #4
    This cannot be solved. There is no equation. That expression needs to equal something otherwise the only thing you can do is simplify it, but that seems to be done already.

  6. Jun 28, 2005 #5


    User Avatar
    Science Advisor
    Homework Helper

    If you mean you want to find an instance where:

    [tex] (b-a-2)e^b + (b-a)e^a = b^2 -2e^b + 6b - a^2 + 2e^a - 6a[/tex]

    I don't think there is an algebraic way of doing it. I would like to note also that a = 0 and b = 0 is not a solution. Various mathematical programs will easily be able to approximate answers.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook