http://www.perlmonks.org?node_id=199

sin

See the current Perl documentation for sin.

Here is our local, out-dated (pre-5.6) version:

sin - return the sin of a number

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sin EXPR

sin

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Returns the sine of EXPR (expressed in radians). If EXPR is omitted, returns sine of $_.

For the inverse sine operation, you may use the POSIX::asin() function, or use this relation:

    sub asin { atan2($_[0], sqrt(1 - $_[0] * $_[0])) }

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