# Knowledge Base

## Solution 12252: Calculating the Log and Inverse Log of a Number Using the TI-30X IIS/B.

### How do I calculate the log and inverse log of a number using the TI-30X IIS/B?

On the TI-30X IIS/B the [LOG] key computes the common logarithm of a number. To compute the common antilogarithm of a number, use the 10x function. The examples below will demonstrate calculating the log and antilog of a number the TI-30X IIS/B.

Example: Calculate the log of 100.

1) Press the [LOG] key.
2) Input 100, and press the [ ) ] key to close parentheses.
3) Press [=] to solve.

The answer is 2.

Example: Calculate the antilog of 2.

1) Press [2nd] [LOG] (10x).
2) Input 2, and press the [ ) ] key.
3) Press [=] to solve.

The answer is 100.

Please Note:: There is not an option to change the base setting on this unit. However, users can use the mathematical identity to perform log calculations using bases other than 10. For example, to find the log of 8 base 2, input Log 8 / Log 2 to find the result.

Please see the TI-30X IIS/B guidebooks for additional information.