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Math Help - Base e

  1. #1
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    Base e

    Here is an easy one for someone to nail.

    Need to solve: In x = -79.93

    I know x = e^-76.93

    but how do i get to the answer 4.93 x 10^-34

    I have an "In" button on my calc., the shift function of this is "e^x".

    Please help.
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  2. #2
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    Hello,

    Quote Originally Posted by chem_student View Post
    Here is an easy one for someone to nail.

    Need to solve: In x = -79.93

    I know x = e^-76.93

    but how do i get to the answer 4.93 x 10^-34

    I have an "In" button on my calc., the shift function of this is "e^x".

    Please help.
    First of all, it's LN, not IN, for "logarithm neperian".

    Then you should have in your calculator (can you tell me which one if you don't find it ?) a button with "e^x", or something alike.
    Otherwise, try exp(...)
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  3. #3
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    Yes I have "e^x" its the shift function of the Ln key.

    So i push shift, then Ln, and the number 1 comes up.
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  4. #4
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    Quote Originally Posted by chem_student View Post
    Yes I have "e^x" its the shift function of the Ln key.

    So i push shift, then Ln, and the number 1 comes up.
    That's strange...
    What calculator do you have ?

    Because if 1 comes up, it means that you typed ln(e)
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  5. #5
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    Ok so I punched in -76.93 and then the function "e^x".

    Got 3.89 x 10^-34

    Teachers answer to the question is 4.93 x 10^-34.
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  6. #6
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    Quote Originally Posted by chem_student View Post
    Ok so I punched in -76.93 and then the function "e^x".

    Got 3.89 x 10^-34

    Teachers answer to the question is 4.93 x 10^-34.
    Because it's 79.93, not 76.93
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  7. #7
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    that gives me 1.94 x 10^35

    damn this.
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  8. #8
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    I was talking about the part without the sign...

    You said in your first message that it was -79.93
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  9. #9
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    I give up.

    Cant get 4.93 x 10^-34 no matter what I do.

    Thanks anyway.
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  10. #10
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    I think the answer your teacher provided you with is false... I've tried it out and it doesn't yield his answer

    Are you sure you copied it well ?

    (%i1) %e^(-79.93);
    (%o1) 1.9357178794122214*10^-35

    (%i2) 10^(-79.93);
    (%o2) 1.1748975549394918*10^-80

    (%i3) 10^(-76.93);
    (%o3) 1.1748975549394913*10^-77

    (%i4) %e^(-76.93);
    (%o4) 3.8879932939808711*10^-34
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