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: Logarithms: ALG2 teacher say what?

  1. May 13, 2008 #1
    I have these questions that are due tomorrow I am completely clueless on what my teacher is asking.

    1. What is log(x), Explain.

    I think that is like a parent function not sure

    2.What is 10^log(10)

    I know that it graphs as a straight line but thats it...


    If anyone happens to recognize these please answer ASAP.



    Note: if the date May, 14 2008 has passed don't bother answering.
  2. jcsd
  3. May 13, 2008 #2


    User Avatar
    Homework Helper
    Education Advisor
    Gold Member

    Study your textbook on the topics of exponential functions and logarithmic functions. They are inverses. Note carefully that 10^x is an exponential function. Its inverse is log(x), where the base is 10. One function will undo its inverse. This means that 10^(log(x))=x and that log(10^x)=x as long as the logarithm in these cases is 10.
  4. May 25, 2008 #3
    1. log(x) is equal to the number that you must raise 10 to in order to get x. 10^(log(x)) = x. Logarithms are exponents.

    2. log(10) = 1, since 10^1 = 10. So 10^(log(10)) = 10^1, or 10.
    Last edited: May 25, 2008
  5. May 28, 2008 #4
    Logarithms are not exponents! They are the inverse of exponents (huge difference!).

    Basically, if [tex]y = \log_{a}(x)[/tex], then [tex]x = a^y[/tex]

    Just like, if [tex]y = x^2[/tex], then [tex]x = \pm \sqrt{y}[/tex]
  6. May 28, 2008 #5


    User Avatar
    Science Advisor

    Nick89, logarithms are exponents.

    They are the inverse of exponential functions and there is a huge difference between "exponential functions" and exponents.

    As you say, if y= loga(x), then x= ay. y, the logarithm is an exponent!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook