diff --git a/src/trig_functions/trig_functions.c b/src/trig_functions/trig_functions.c
index 7f12327..186a4fe 100644
--- a/src/trig_functions/trig_functions.c
+++ b/src/trig_functions/trig_functions.c
@@ -12,5 +12,6 @@ double calculate_cos(double angle) {
 }
 
 double calculate_tan(double angle) {
-    return tan(angle);
+    if (angle==0) return 0;
+    else return tan(angle);
 }