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

Homework Help: Help with definate integration problem

  1. Jan 26, 2009 #1
    1. The problem statement, all variables and given/known data

    [tex]\int[/tex]10[tex]^{t}[/tex]dt t = [1,2]

    2. Relevant equations

    I know that [tex]\int[/tex](a[tex]^{x}[/tex])dx = [tex]\frac{(a^x)}{ln(x)}[/tex] + C and x[tex]\neq[/tex] 1

    3. The attempt at a solution

    I could do this problem as indefinate, but since the restraints include a "1", I can't plug it into the the integral because it will result in a "0" being in the denominator. The answer in the back of the book shows:

    [tex]\frac{90}{ln(10)}[/tex]

    Should I be using a substitution rule somewhere?
     
    Last edited: Jan 26, 2009
  2. jcsd
  3. Jan 26, 2009 #2

    Gib Z

    User Avatar
    Homework Helper

    Well, the equation in your section 2 is actually incorrect, the x and a's should be switched around ( or the dx replaced with da). That solves the problem !
     
  4. Jan 26, 2009 #3
    sorry never mind, its supposed to be the ln(a) not x
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook