What is the inverse log of 1.48? - Texas Instruments TI-89 Calculator

The inverse common log is the shifted function of the "log" key. The inverse natural log is the shifted function of the "ln" key.

By 'log inverse', you presumably mean the inverse of the logarithm function. There are two logarithm functions on most scientific calculators. Firstly [ln], or natural logarithms, to the base e, where the inverse is e^x. Secondly [log], or logarithms to the base 10, where the inverse is 10^x.

Example 1 : ln(2) = 0.69314718 so e^0.69314718 = 2
Example 2: log(2) = 0.301029995 so 10^0.30102995 = 2

The inverse of the log function is the power function.
For log in base 10 that inverse is 10 to a power of
More generally, let b be the base of the logarithm. If y=log_b (x) then x=b^y
For your case log=log_10, to calculate the inverse you perform 10^(-2)=0.01=1/100
On calculators the log in base 10 and its inverse share the same physical key. One is accessed directly, the other is the shifted key function.

Depending on the actual log function you are talking about, the inverse function (what you call the anti log) can be one of several things.
The inverse of the natural log (LN) is the exponential function e^x.
If y= ln(x) then x=e^y
On a calculator functions that are inverse of one another share the same physical key. If one function is marked on a key, the inverse function is usually the SHIFTED (or 2nd) key
The inverse of the common (decimal logarithm) is the power function with 10 as base.
Example: if y= log(x) then x=10^y
For an arbitrary base (must be positive) if y= log_b(x) then x=b^y.
Note: I do not think that the FX-300ms can perform log calculations in bases other than e (natural log) or 10 (common decimal log).

For the inverse natural log, press 2nd LN. For the inverse common log, press 2nd LOG.

For example, to calculate the inverse natural log of 2, press 2nd LN 2 ENTER and you'll get about 7.389 .

Press the log key, enter a poistive number and press the = key.
To calculate the inverse of the decimal log use SHIFT LOG to access the function 10^x (the inverse of the log function.)

The log base 10 function has an inverse: It is the 10 ^x function. It shares the same physical key with the decimal log. Use [SHIFT][LOG].
The natural log (LN) has an inverse alos and that it the exponentila function e^x. It shares the same physical key with it.

Hello,
If you want to do correct mathematics you should strive to use the right words to express the concepts, and the right symbols too. While the logarithm function has an inverse function, it is never called an inverse log and it is never represented as log^-1. (I know you are going to protest and claim that the inverse of a sine function is represented on calculators by sin^-1. This a manufacturer shortcut, and we have no power to change that.) HP uses ASIN, ACOS, ATAN. These are still manufacturer shortcuts but they induce fewer errors.
Anyway, the logarithm functions do have inverse functions.

1. Natural loogarithm (ln)

The inverse of the natural log is the exponential.
ln(e^(x))=e^(ln(x)) =x

2. Common logarithm (logarithm in base 10)
The common logarithm has an inverse function, often called the antilogarithm or antilog.

There is an equivalence.
y=log(x) <--> x=10^(y)

From what I undesrtand of your exemple, you are looking for the antilog of the number -0.4/10 (or -0.04.)

-0.04= log(x), what is x?
You use the equivalence above to look for x as follows.
x=10^(-0.04) =0.9120108394.
Use the change sign (-) not the regular MINUS sign.

Take the log of the last result (still stored in Ans memory) and you get the original number.


Hope it helps.

The inverse of the common log is the raise 10 to a power. the inverse of the natural log is the exponential. The log and the antilog share the same key, one is accessed directly the other as a seconf/shifted function. Same thing for the natural log (ln) and the exponential.

Press "2nd LN" which gives you the exponential (inverse natural log) of 7.41 = 1652.426....

Pressing LN will give you back 7.41

Same procedure to use logs to base 10, use LOG and 2nd LOG