SOLUTION: Hi could someone please help me with this problem? x=e^-7.85 my teacher saids the answer is 3.90* 10^-4 I don't understand how she got this

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Hi could someone please help me with this problem? x=e^-7.85 my teacher saids the answer is 3.90* 10^-4 I don't understand how she got this       Log On


   

Question 121265This question is from textbook beginning and intermediate algebra
: Hi could someone please help me with this problem?
x=e^-7.85 my teacher saids the answer is 3.90* 10^-4 I don't understand how she got this This question is from textbook beginning and intermediate algebra

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
Hi could someone please help me with this problem?
x=e^-7.85 my teacher said the answer is 3.90* 10^-4
I don't understand how she got this 


I have a TI-84 calculator.  I'm guessing yours is similar.

After clearing the screen, I hit the 2nd key and then
the key which has LN on it with ex above
it.  Then I see

e^(

so then I type -7.85 and close the parentheses with a )

Then when I press ENTER I see

3.897519683E-4

We round off the first part to 3.90 and we interpret the
E to stand for "Exponent of 10" which represents "×10^"
and we have

3.90 × 10-4

Edwin