Logarithm and exponential functions are two sides of the same story, and among the widely used mathematical functions in science and engineering.

The function for the logarithm ln(x) is called LN(), i.e. if you need to calculate ln for a value in a cell you write =LN() in the cell, and in the bracket you write the name of the cell and/or mathematical expression you want to have processed.

For**Microsoft Excel** it looks like this:

For**OpenOffice Calc** it looks like this:

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The function for the common logarithm, log(x), or base-10 logarithm, which is log_{10}(x), is called LOG10(), i.e. if you need the cell to calculate the log value you write =LOG10() in the cell, and in the bracket, you write the name of the cell and/or mathematical expression you want to have processed.

For**Microsoft Excel** it looks like this:

For**OpenOffice Calc** it looks like this:

The function LOG() can also be used for the common logarithm. The function is really a generic function, as seen in the next section, but it is worth noticing, that if you don't specify the base number for the logarithm, the function uses base-10 as default.

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The function LOG() can also be used for the common logarithm. The function is really a generic function, as seen in the next section, but it is worth noticing, that if you don't specify the base number for the logarithm, the function uses base-10 as default.

Besides ln(x) and log(x), you can on occasion need other logarithms. Log(x) is implicit log_{10}(x), i.e. the base-10 logarithm, and if you need e.g. log_{5}(x), this is also doable. The syntax is LOG(value ; base), i.e. if you need the base-5 logarithm to the number 10, it looks like this: LOG(10;5). It is possible to insert both cell numbers and calculation for both the value and the base number, if needed. So, if you need log_{5}(x) where x is the value in cell B2, it looks like this:

For**Microsoft Excel** it looks like this:

For**OpenOffice Calc** it looks like this:

**If no value is specified as the base number, the function uses 10 as the default value.**

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Exponential functions, i.e. a number to the power of x, can be done in two ways, depending on whether it is *e*^{x} or one of the other exponential functions.

If we start with*e*^{x}, which is also **inverse ln(x)**, then the syntax is EXP(), i.e. if you need to calculate *e*^{cell B2}, it is EXP(B2).

For**Microsoft Excel** it looks like this:

For**OpenOffice Calc** it looks like this:

Exponential functions that are not*e*^{x}, is written using a circumflex, i.e. this character: ^. Thus, if you have the function 5^{x}, where x is the value in cell B2, the syntax is 5^(B2). This is equivalent to the function inverse log_{5}(x).

For**Microsoft Excel** it looks like this:

For**OpenOffice Calc** it looks like this:

Should you need**inverse log(x)**, which is really inverse log_{10}(x), for the value in cell B2, the syntax is just 10^(B2).

For**Microsoft Excel** it looks like this:

For**OpenOffice Calc** it looks like this:

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Exponential functions that are not

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