mirror of https://github.com/mkerrisk/man-pages
38 lines
866 B
Groff
38 lines
866 B
Groff
.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
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.\" Distributed under GPL
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.\"
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.TH CATAN 3 2008-08-11 "" "Linux Programmer's Manual"
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.SH NAME
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catan, catanf, catanl \- complex arc tangents
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.SH SYNOPSIS
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.B #include <complex.h>
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.sp
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.BI "double complex catan(double complex " z );
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.br
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.BI "float complex catanf(float complex " z );
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.br
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.BI "long double complex catanl(long double complex " z );
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.sp
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Link with \fI\-lm\fP.
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.SH DESCRIPTION
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The
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.BR catan ()
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function calculates the complex arc tangent of
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.IR z .
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If \fIy\ =\ catan(z)\fP, then \fIz\ =\ ctan(y)\fP.
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The real part of y is chosen in the interval [\-pi/2,pi/2].
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.LP
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One has:
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.nf
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catan(z) = 1 / 2i clog((1 + iz) / (1 \- iz))
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.fi
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.SH VERSIONS
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These functions first appeared in glibc in version 2.1.
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.SH "CONFORMING TO"
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C99.
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.SH "SEE ALSO"
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.BR ccos (3),
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.BR clog (3),
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.BR complex (7)
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