I cannot figure out how to get the log key to look like this..log^-1. In my text book it said something about the ln button. That didn't work. Please help.

Let me give you a general recipe to familiarize yourself with any calculator, if you are averse to reading the manuals.
Most function will work in one of two ways.
1st way
Enter the number, then press the key,; the result is displayed.immediately.

Second way
Press the function key ( a left parenthesis may be displayed) enter the number (close the right parenthesis if there was a left one) press the = or EXE or ENTER keys.

Try the two ways described above to calculate the following values. The answers are given. Here log is he decimal logarithm and ln is the natural logarithm.


log(1)=0
ln(1)=0
ln(2)=0.693147181
log(2)=0.301029996
ln(100)=4.605170186

log(10)=1 (= number of zeros after the 1)
log(100)=2. (= number of zeros after the 1)
log(1000)=3 (number of zeros after the 1)
log(10000)=4 (number of zeros after the 1)

Shift LN raises e (about 2.718) to a power. Try this:
1 . 0 5 9 5 ^ 2 . 5 =

^ is the key to the left of the log key, below the big cursor pad.

Pressing 2 0 0 LN = will give you the natural logarithm of 200. If you need the common (base 10) logarithm, divide the result by the log of 10.

( 2 0 0 LN ) / ( 1 0 LN ) =
will give you the common log of 200.

The BA II+ does not have a key for the common logarithm function. You can calculate the common log of a number by calculating its natural log and then dividing by the natural log of 10.

log10(x) = ln(x)/ln(10)

The same procedure works for logarithms to any base.

There is no common logarithm key. You can compute the common (base 10) log of any number by using the relationship log(x) = ln(x) / ln(10).

For example, to compute the log of 2, type 2 LN / 1 0 LN =

The natural log is the LN key, located just to the left of the 7 key.

To calculate the common log, use the relationship log(x) = ln(x)/ln(10).

To calculate the natural log of 3, press 3 LN

To calculate the common log of 3, press 3 LN / 1 0 LN =

To use Natural Log on the Scientific Texas Instruments, you may need to enter your number first (which is counter-intuitive). E.g. ln 1, press "1" first, and then the LN key.

The button itself is right beside the OFF button. To access the "e to the x" (notice written in yellow just behind it) you would need to hit the 2ND button first.

The natural log is the LN key, located just to the left of the 7 key.

To calculate the common log, use the relationship log(x) = ln(x)/ln(10).

To calculate the natural log of 3, press 3 LN

To calculate the common log of 3, press 3 LN / 1 0 LN =

If you have the latest version of the firmware (2.53) you can use the logBASE function available in the CATALOG. If you don't have the latest firmware, you can get it from http://education.ti.com

Regardless of the firmware version, you can always compute the logarithm to any base by using the relationship

logb(x) = log(x)/log(b) = ln(x)/ln(b)

The TI-83+ has keys for natural and common logarithms (base e and 10, LN and LOG, respectively). If you want to calculate the logarithm to another base, you have to use the relationship

LOGb(x) = LOG(x)/LOG(b) = LN(x)/LN(b)