diff --git a/src/trig_functions/trig_functions.c b/src/trig_functions/trig_functions.c
index ffae719..7f12327 100644
--- a/src/trig_functions/trig_functions.c
+++ b/src/trig_functions/trig_functions.c
@@ -7,7 +7,8 @@ double calculate_sin(double angle) {
 }
 
 double calculate_cos(double angle) {
-    return cos(angle);
+    if (angle==0) return 1;
+    else return cos(angle);
 }
 
 double calculate_tan(double angle) {