– WE WANT TO EVALUATE

THE GIVEN LOGARITHMS, AND THEN WRITE

AN EXPONENTIAL EQUATION TO SHOW THE MEANING

OF THE VALUE. NOTICE BOTH OF THESE

ARE NATURAL LOGARITHMS, WHICH MEANS BOTH OF THESE

ARE LOG BASE E. AND JUST TO REMIND US OF THIS, LET’S GO AHEAD AND PUT

THE LITTLE E HERE AND HERE. THE GOOD NEWS

IS MOST CALCULATORS CONTAIN A COMMON LOG BUTTON AS

WELL AS A NATURAL LOG BUTTON. SO IF WE GO TO THE CALCULATOR,

TO EVALUATE NATURAL LOG 7, WE COULD JUST PRESS LN, 7,

CLOSE PARENTHESIS, AND PRESS ENTER. WE DO WANT TO ROUND

TO THE HUNDREDTHS, SO THIS WILL BE APPROXIMATELY

1.95. TO HELP US TO UNDERSTAND

THE MEANING OF THIS, WE NOW WANT TO WRITE THIS

LOG EQUATION AS AN EXPONENTIAL EQUATION. AND THERE ARE SOME NOTES HERE

TO HELP US IF WE NEED IT. BUT E WOULD BE THE BASE, THE EXPONENT WOULD BE

APPROXIMATELY 1.95, AND THIS WOULD BE

APPROXIMATELY EQUAL TO THE NUMBER 7. WE’RE SAYING APPROXIMATELY

BECAUSE WE DID ROUND THIS. AGAIN, E TO THE 1.95 WOULD BE

=TO APPROXIMATELY 7. WE CAN GO AHEAD AND VERIFY THIS

ON THE CALCULATOR AS WELL. IF WE PRESS SECOND NATURAL LOG IT’LL BRING UP E RAISED TO THE

POWER OF 1.95, PRESS ENTER. NOTICE HOW IT IS

APPROXIMATELY 7. IT IS A LITTLE BIT LARGER

BECAUSE WE DID ROUND UP WHEN ROUNDING

TO THE HUNDREDTHS. FOR OUR SECOND LOGARITHM,

WE’LL TYPE IN LN, 0.25, CLOSE PARENTHESIS, ENTER. AND AGAIN, ROUNDING

TO THE HUNDREDTHS WE’D HAVE APPROXIMATELY -1.39. AND NOW TO WRITE

THE EXPONENTIAL EQUATION, THE BASE IS E,

THE EXPONENT IS -1.39, AND THIS SHOULD BE

APPROXIMATELY EQUAL TO THE NUMBER 0.25. LET’S GO AHEAD

AND VERIFY THIS AS WELL. SO SECOND LN, -1.39, CLOSE

PARENTHESIS, PRESS ENTER. AND NOTICE HOW THE VALUE

IS APPROXIMATELY 0.25. AGAIN, E RAISED TO THE POWER

OF -1.39 IS APPROXIMATELY 0.25.

You are so awesome, just found your video library…. WONDERFUL!!! Thank you soo much, love the videos, very easy to understand. God Bless You. Eboni

Very helpfull…………………

my TI-84 Plus CE calculator will calculate the answer when using ln, but when I enter e^-1.39 it will not solve it. What settings do I need to change to have it work on both parts of this problem? THANKS!