How to Find Log 10 of a Negative Number
- 1). Write the data points on which you want to carry out a log transformation. For example, "-7, -3, 0, 17, 21."
- 2). Identify your greatest negative data point. In the provided example, your greatest negative data point is -7.
- 3). Remove the negative sign from the data point and add 1 to it: 7 + 1 = 8.
- 4). Add your answer to each of your data points: -7 + 8 = 1; -3 + 8 = 5; 0 + 8 = 8; 17 + 8 = 25; 21 + 8 = 29.
- 5). Write the answers as your new data points: "1, 5, 8, 25, 29."
- 6). Press the Log button on a scientific calculator, such as the Texas Instruments TI-83 Plus. The Log button will always take the base-10 log of the positive number you enter.
- 7). Type in the first negative data point that is now positive and press "Enter."
- 8). Read your answer.
- 9). Write your answer as the log of your first negative data point.
- 10
Find the log of each following data point. Write the completed logs of your data points, including the negative and zero data points. In the provided example, you will write: "0, 0.69897, 0.90308, 1.23044, 1.32221."