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<td width="20%">[[Ruby Operator Precedence|Previous]]<td align="center">[[Ruby Essentials|Table of Contents]]<td width="20%" align="right">[[Understanding Ruby Logical Operators|Next]]</td>
<tr>
<td width="20%">Ruby Operator Precedence<td align="center"><td width="20%" align="right">Understanding Ruby Logical Operators</td>
</table>
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<htmlet>ruby</htmlet>
The Ruby ''Math'' module provides the Ruby programmer with an extensive range of methods for performing mathematical tasks. In addition, the ''Math'' module includes two commonly used mathematical constants.
== Ruby Math Constants ==
The Ruby ''Math'' module includes common math constants. A list of constants may be accessed using the ''constants'' method:
<pre>
Math.constants
=> ["E", "PI"]
</pre>
As we can see, as of the current version of Ruby, only two constants are defined. We can access these using :: notation:
<pre>
Math::PI
=> 3.14159265358979
Math::E
=> 2.71828182845905
</pre>
== Ruby Math Methods ==
As mentioned previously, Ruby provides an extensive range of math related methods. These are listed and described in the following table.
<htmlet>adsdaqbox_flow</htmlet>
<table border="1" cellspacing="0">
<tr style="background:#efefef;">
<th>Method name<td> Description</th></tr>
<tr><td>Math.acos, Math.acos!<td>Arc cosine</td></tr>
<tr><td>Math.acosh, Math.acosh! <td>Hyperbolic arc cosine</td></tr>
<tr><td>Math.asin, Math.asin! <td>Arc sine</td></tr>
<tr><td>Math.asinh, Math.asinh <td>Hyperbolic arc sine</td></tr>
<tr><td>Math.atan, Math.atan!, Math.atan2, Math.atan2! <td>Arc tangent. atan takes an x argument. atan2 takes x and y arguments</td></tr>
<tr><td>Math.atanh, Math.atanh! <td>Hyperbolic arc tangent</td></tr>
<tr><td>Math.cos, Math.cos! <td>Cosine</td></tr>
<tr><td>Math.cosh, Math.cosh <td>Hyperbolic cosine</td></tr>
<tr><td>Math.sin, Math.sin! <td>Sine</td></tr>
<tr><td>Math.erf <td>Error function</td></tr>
<tr><td>Match.erfc <td>Complementary error function</td></tr>
<tr><td>Math.exp, Math.exp! <td>Base x of Euler</td></tr>
<tr><td>Math.frexp <td>Normalized fraction and exponent</td></tr>
<tr><td>Math.hypot <td>Hypotenuse</td></tr>
<tr><td>Math.ldexp <td>Floating-point value corresponding to mantissa and exponent</td></tr>
<tr><td>Math.sinh, Math.sinh! <td>Hyperbolic sine</td></tr>
<tr><td>Math.sqrt, Math.sqrt! <td>Square root</td></tr>
<tr><td>Math.tan, Math.tan! <td>Tangent</td></tr>
<tr><td>Math.tanh, Math.tanh! <td>Hyperbolic tangent</td></tr>
</table>
== Some Examples ==
Now that we have a list of the math methods available to us, we can start to use them:
To perform a square root:
<pre>
Math.sqrt(9)
=> 3.0
</pre>
Or a Euler calculation:
<pre>
Math.exp(2)
=> 7.38905609893065
</pre>
== Summary ==
This chapter has covered the concepts behind Ruby methods and functions. The next chapter will focus on Ruby logical operators.
<htmlet>ruby</htmlet>
<hr>
<table border="0" cellspacing="0" width="100%"><tr>
<td width="20%">[[Ruby Operator Precedence|Previous]]<td align="center">[[Ruby Essentials|Table of Contents]]<td width="20%" align="right">[[Understanding Ruby Logical Operators|Next]]</td>
<tr>
<td width="20%">Ruby Operator Precedence<td align="center"><td width="20%" align="right">Understanding Ruby Logical Operators</td>
</table>
