If you need to calculate the logarithm based on a number other than 10, you should use the base conversion formula. For example, to calculate the base 7 logarithm of 12, the operation on the calculator should be (log 12)/(log7).

From the process of logarithmic invention, we can see that the needs of social production and science and technology are the main driving force for the development of mathematics. The process of establishing the relationship between logarithm and exponent shows that it is very important to use a good symbol system for the development of mathematics.

In fact, good mathematical symbols can greatly save people's thinking burden. Mathematicians have made long and arduous efforts to develop and improve the mathematical symbol system.

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Brand classification:

There are only four manufacturers that independently develop and produce calculators in the world: Casio, Texas Instruments (TI), Hewlett-Packard (HP) and Sharp. The function calculators outside these four manufacturers are imitations, knockoffs or pirates.

Among the four major manufacturers, Casio's functional science calculator is the most popular. At present, the CLASSWIZ series functional science calculators produced by Casio are at the highest level, and the domestic flagship model is Casio fx-99 1CNX, which has rich calculation functions and Chinese menus.

It is suitable for middle school students and can be used in exams that do not require programming and storage functions. In addition, fx-99 1ESPLUS of Casio and TI-36XPro of Texas Instruments are also popular advanced functional science calculators. There are also some models suitable for junior high school students, such as Casio fx-82ESPLUSA, fx-82CNX and so on.

Baidu encyclopedia-logarithm