From c6518823c465f50dd61691a4984de32a87c42633 Mon Sep 17 00:00:00 2001
From: Markus Gans <guru@server.home.net>
Date: Mon, 22 Jun 2015 02:01:50 +0200
Subject: [PATCH] Improve trigonometric function zero-crossing

---
 test/calculator.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test/calculator.cpp b/test/calculator.cpp
index 3011fe5b..da5c3b68 100644
--- a/test/calculator.cpp
+++ b/test/calculator.cpp
@@ -565,6 +565,8 @@ void Calc::cb_buttonClicked (FWidget*, void* data_ptr)
       {
         if ( arcus_mode )
           *x = asin(*x) * 180.0L/PI;
+        else if ( fmod(*x,180.0L) == 0.0L )
+          *x = 0.0L;
         else
           *x = sin(*x * PI/180.0L);
       }
@@ -595,6 +597,8 @@ void Calc::cb_buttonClicked (FWidget*, void* data_ptr)
       {
         if ( arcus_mode )
           *x = acos(*x) * 180.0L/PI;
+        else if ( fmod(*x - 90.0L,180.0L) == 0.0L )
+          *x = 0.0L;
         else
           *x = cos(*x * PI/180.0L);
       }