- publishing free software manuals
Perl Language Reference Manual
by Larry Wall and others
Paperback (6"x9"), 724 pages
ISBN 9781906966027
RRP £29.95 ($39.95)

Sales of this book support The Perl Foundation! Get a printed copy>>>

sqrt EXPR

sqrt

Return the positive square root of EXPR. If EXPR is omitted, uses $_. Works only for non-negative operands unless you've loaded the Math::Complex module.

use Math::Complex;
print sqrt(-4);    # prints 2i
ISBN 9781906966027Perl Language Reference ManualSee the print edition