[gnumeric] R.QCAUCHY: improve accuracy.

[Morten Welinder <mortenw src gnome org>]

commit 7bafd2948b22b61c609310495fb739e4103ae130
Author: Morten Welinder <terra gnome org>
Date:   Fri Jan 10 23:08:32 2014 -0500

    R.QCAUCHY: improve accuracy.

 NEWS                   |    1 +
 plugins/fn-r/ChangeLog |    4 ++++
 plugins/fn-r/extra.c   |    2 +-
 3 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 27239bb..df41032 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,7 @@ Morten:
        * Fix win32 print crash.  [#719997]
        * Fix solver problem with constraints.
        * Improve accuracy of R.PNORM and R.PLNORM for large arguments.
+       * Improve accuracy of R.QCAUCHY.
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.9
diff --git a/plugins/fn-r/ChangeLog b/plugins/fn-r/ChangeLog
index a8a3db3..24657e5 100644
--- a/plugins/fn-r/ChangeLog
+++ b/plugins/fn-r/ChangeLog
@@ -1,3 +1,7 @@
+2014-01-10  Morten Welinder  <terra gnome org>
+
+       * extra.c (qcauchy): Use gnm_tanpi.
+
 2013-11-28  Morten Welinder <terra gnome org>
 
        * Release 1.12.9
diff --git a/plugins/fn-r/extra.c b/plugins/fn-r/extra.c
index 03c64cc..427cbcb 100644
--- a/plugins/fn-r/extra.c
+++ b/plugins/fn-r/extra.c
@@ -30,7 +30,7 @@ qcauchy (gnm_float p, gnm_float location, gnm_float scale,
                lower_tail = !lower_tail;
        }
        if (lower_tail) scale = -scale;
-       return location + scale / gnm_tan(M_PIgnum * p);
+       return location + scale / gnm_tanpi (p);
 }
 
 /* ------------------------------------------------------------------------- */