Question about Texas Instruments TI-83 Plus Calculator

# How to find a log of a different base - Texas Instruments TI-83 Plus Calculator

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Use the logBASE function available in the MATH menu. Press MATH, use cursor-left/right to select the MATH submenu, then use cursor-up/down to access logBASE.

Posted on Jun 08, 2014

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Posted on Jan 02, 2017

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## Related Questions:

Tip

### The Log function!!

I calculators you can't change or set the base of 'log' is default 10 so you need to know these:

log x (base y) = log x / log y

when log x it's automatic log x (base 10) here some examples:

log 8 (base 2) = log 8 / log 2
log 27 (base 3) = log 27 / log 3

and the base it's default 10 again, and that is how you need to use it in calculators(no bases), and here the explanation to this:

log x (base y) = log x (base 10) / log y (base 10) = (log x / log 10) / (log y / log 10) = (log x / log 10) * (log 10 / log y) = log x / log y

here so other stuff about 'log' :

log (x*y) = log x + log y
log (x/y) = log x - log y

Hope it's helped

on Jul 07, 2009 | Casio fx-300ES Calculator

### How do I find log with a different base (not 10)?

Calculate the log (base 10) of the number, then divide the result by the log (base 10) of the base.
For example, to calculate the base-3 log of 9, calculate the log of 9 to get 0.954 . Divide that by the log of 3 (about 0.477) to get 2.0 .
Since 9 is 3 squared, the log base 3 of 9 is 2, as we just calculated.

Mar 28, 2012 | Office Equipment & Supplies

### How do I do logs with different bases (bases other than 10)

Most calculators can't do logs in different bases, but you can solve for the answer this way:

Let's say you need to take the log of 5 in base 3. This can also be written as log5 (base 10)/log3 (base 10).

A more technical solution can be found here: http://oakroadsystems.com/math/loglaws.htm#NewBase

May 25, 2011 | Casio FX-9750GPlus Calculator

### How to enter a different log base (other than base e or base 10) into the Texas Instrument TI-80 silver

The TI-83 doesn't have such a function built-in. Use the relationship logb(x) = log(x)/log(b) = ln(x)/ln(b).

May 13, 2010 | Texas Instruments TI-83 Plus Calculator

### How to enter a different log base (other than base e or base 10) into the Texas Instrument TI-80 silver

You cannot. You must use the formula
log in base b of a =log(a)/log(b) or
log_b(a)=ln(a)/ln(b)
where log(a) is common logarithm of a and ln(a)= natural logarithm of a

If you had the TI84PLUS or TI84PLUS SE, you could have installed the newest OS upgrade and that upgrade uses math print which allows the user to calculate logarithms in any base directly.

Mar 22, 2010 | Texas Instruments TI-83 Plus Calculator

### How do you compute Log base 5 to the exponent 5.9? i cant figure it out on this computer

Hello,
There is something missing in the formulation.

Any way you cannot calculate it directly on this calculator.You need to use the formula

log_5 (a)= ln(a) x log_5 (e) a is a positive integer

where log_5 means log in base 5 (my notation for the function)
e is the base of the natural logarithms (e=2.71928 )
ln is the natural log function

To obtain a more accurate value of e, calculate e^(1)
Here are some values of log(e) in different bases (for you to play with)

log_2(e)= 1.442695041
log_3(e)=0.9102392266
log_4(e)=0.7213475204
log_5(e)=0.6213349346
log_6(e)=0.5581106266
log_7(e)=0.5138983424
log_8(e)=0.4808983470
log_9(e)=0.4551196133
log_10(e)=log(e)=0.4342944819

If you have to use log in bases other than 10 or e, you will need a claculator that does that at the touch of a button. Some calculators that handle these calculations are the Casio FX-300ES, FX-115ES,FX-991ES, those called Natural Display, or WriteView(Sharp) or Textbook display.

Hope it helps.

Sep 03, 2009 | Texas Instruments TI-30XA Calculator

### I need help with a change of base formula problem.

It's simple here some logs:

log x base y = log x / log y
log (x*y) = log x + log y
log (x/y) = log x - log y
you just need to know that the default base of log in calculators is 10, so log x mean
log x base 10 = log x / log 10,
so write log x / log y for log x base y example:
log 8 base 2 = log 8 / log 2 that is how you write it on calculator, hope it was helpful

Jul 01, 2009 | Texas Instruments TI-83 Plus Calculator

### How to calculate logarithm values with different base

Like you maybe know in math (I know!) log x base y = log x / log y
so what you need its just input your number (x for example) and log it, than divide log x by log 2.
just: log x / log 2. (by the way in calculator the meaning of log x is log x base 10 the default base is 10)

Jun 05, 2009 | Casio FX-300MS Calculator

### How to calculate log value in calculator with different base value

In any scientific calculator log2(n) can be  calculated with either ln or log function as follows

Log2(n)= ln(n) / ln(2)

Or
Log2(n)=log(n) / log(2)

both will give nearly the same answers

Dec 08, 2007 | Casio FX-300MS Calculator

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