Tuesday, November 10, 2009

Logs and Inverses

1) Logs
  • The inverse of B^x
  • All Logarithm functions pass through (1,0) because anything to the power of 0 is 1
2)Inverses
  • The equation for Inverses is f(x)= f^-1(x)
  • the Output and the input change positions. Y is X and X is Y
  • Symmetrical on a graph with the original function on the Y=X line
  • Slope is consistent between the symmetrical functions.
  • Not all functions have inverses.
Things I do not understand
  • When using Ln or Log do you always (exponiate) (spelling error )the previous equation?
  • Does Log X always have to be the same on the other side of the equation ?
  • What are some things to eliminate before attempting to solve the Log function ?

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9 comments:

  1. Stephanie HerreraNovember 14, 2009 at 1:32 AM

    In order to solve for log then one must eliminate both sides of log by implying either ln or e...okay an example of dealing with ln but im not 100% is right:
    ln(y-1)-ln2=(x+lnx)e
    (y-1)-ln2= ex+x
    +ln2=ex+x+ln2
    y-1=ex+x+ln2
    +1 +1
    y=ex+x+ln2+1
    i would of believed we needed to cancel out ln on both sides but apparently thats what the books answer is..

    ReplyDelete
  2. Martha CarbajalNovember 14, 2009 at 10:14 PM

    I dont belive that he Log of X has to be the same one both sides... in order to cancel it out i think it does.....

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  3. Ruben CejaNovember 14, 2009 at 10:28 PM

    umm i think other things to eliminated before starting to work with the ln or log is the i guess what you could call the coefficient in that first get rid of that then, you can start the process :)

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  4. Steven GarciaNovember 14, 2009 at 10:51 PM

    its not the same its just so that u can get x alone or solve for it

    ReplyDelete
  5. JoyceRojasNovember 15, 2009 at 2:05 PM

    you are so smart. i also had problems with things that u didnt get

    ReplyDelete
  6. AnonymousNovember 16, 2009 at 6:28 PM

    Well you want to eliminate the simple stuff like a "+2" or a "/2" simple stuff like addition and subtraction before the log. Sometimes you need to attack the log first though

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  7. Henry MontielNovember 18, 2009 at 11:10 PM

    isn't used to cancel right but first start easy if possible then go to the log

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  8. HwangDecember 8, 2009 at 10:45 AM

    "Slope is consistent between the symmetrical functions."

    What do you mean here?

    And like others said, you want to get the log function with only it's input by itself first before "exponentiating" both sides.

    ReplyDelete
  9. HwangDecember 8, 2009 at 10:46 AM

    that's not a real word btw. Just making sure.

    ReplyDelete

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