# Advice 1: How to calculate logarithm on a calculator

Logarithm number b for the base a is defined as a measure of the degree to which it is necessary to build a base a, to obtain the number b. As a rule, modern calculators allow you to calculate logarithms base 10 and e, that is, decimal (log) and natural (ln) logarithms , respectively. You will need
• Calculator, basic knowledge in mathematics.
Instruction
1
Check whether a calculator to count the logarithms. Typically, this can do the more advanced versions or engineering calculators. Very easy to find out whether a calculator to count the logarithms. If so, he has a button that says ln and log.
2
After you verify that the calculator allows to count the logarithms, enable it and enter the number whose logarithm you want to calculate. Suppose you want to find the decimal logarithm of the number 324. The digits on the calculator 324.
3
Then click on the "log" if you want to find the logarithm or the button "ln" - if it's real. After that, the calculator will calculate the and the screen shows the answer. In the example number 324 if you count the decimal logarithm, get answer 2.5104, and if natural, then 5.7807.
Note
The logarithm of the number equal to or less than zero, there is no calculator in this case will give you an error.
Easy to mind can calculate the logarithm of a unit, he is always equal to 0, and logarithms, which are a power base. They will simply be equal to this degree.

# Advice 2 : How to calculate logarithm

The calculation of logarithms can be necessary for finding the values according to equations containing unknown variables exponents. Two kinds of logarithms, unlike all the others, have their own names and symbols, is the logarithm to bases 10 and the number e (irrational constant). Consider a few easy ways to calculate logarithm base 10 - decimal logarithm. Instruction
1
Use for calculations the calculator built into the Windows operating system. To run it press the Windows key, select "Run" from the main menu system, enter the Latin letter calc and click OK. In the standard interface, this program does not function calculation algorithms, so open it in menu "View" (or press alt + "and") and select "scientific" or "engineering".
2
Enter the number which should stand under the sign of the decimal logarithm, and click the button marked in the interface that says log. The calculator will calculate and show the result.
3
Use any online service if your computer is connected to the Internet. The network has a huge number of sites with calculators of all kinds. Go, for example, on the page http://kalkulyatoronline.ru/index.html and press end to skip the description of the calculator and go directly to the calculation. Enter a number, the logarithm of which is necessary to calculate, and click the button same as in a software calculator that says log. The result will see immediately - the service does not send data to the server, and computes all directly in your browser.
4
If for some reason you do not want to calculate a logarithm as a logarithm base 10, we can represent it as the quotient of the logarithm base e (Euler's number) this number, the logarithm base e of 10. Logarithms with base e are called "natural" lg(x)=ln(x)/ln(10). To calculate the logarithm of this unconventional way to go, for example, on the website of the search engine Google and type in the search query string ln(81)/ln(10) if you want to find out the decimal logarithm of the number 81. Google, by the way, can you count it in the usual way, that is, if you enter a query lg 81. In both cases, the result is the same: 1,90848502.
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