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Advanced Functions Logarithms

  • Thread starter BlackOut07
  • Start date
  • #1

Homework Statement



A security PIN code is four digits long. Each digit could have the value 0 to 9. if an office building needs 10 security PINs, express the number of codes in logarithmic form with base 10


The Attempt at a Solution



y=4log(x-10)

I don't know how to do the question, but my best attempt produced what you see above.

4 represents the # of digits.
x-10 because of the range 0-9.
 

Answers and Replies

  • #2
HallsofIvy
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What was your reasoning behind "x- 10"?

There are [itex]10^1= 10[/itex] one digit numbers, 0 to 9.

There are [itex]10^2= 100[/itex] two digit numbers, 00 to 99.

There are [itex]10^3= 1000[/itex] three digit numbers, 000 to 999.
 

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