diff --git a/src/runtime.h b/src/runtime.h
index 90e1ed6..44b6133 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -1845,17 +1845,17 @@ static NUMBER ___atan(NUMBER a)
 
 static NUMBER ___sinhd(NUMBER a)
 {
-	return radians_to_degrees(sinh(a));
+	return sinh(degrees_to_radians(a));
 }
 
 static NUMBER ___coshd(NUMBER a)
 {
-	return radians_to_degrees(cosh(a));
+	return cosh(degrees_to_radians(a));
 }
 
 static NUMBER ___tanhd(NUMBER a)
 {
-	return radians_to_degrees(tanh(a));
+	return tanh(degrees_to_radians(a));
 }
 
 static NUMBER ___sinh(NUMBER a)
diff --git a/tests/trig.cog b/tests/trig.cog
index ba5d947..2267f57 100644
--- a/tests/trig.cog
+++ b/tests/trig.cog
@@ -58,32 +58,32 @@ Print If == 10 Tan Atan 10
 else
       "FAIL: Radian arctan";
 
-Print If == 0 Sinhd 0
+Print If == 0.17542037193601015 Sinhd 10
       "PASS: Degree hyperbolic sin"
 else
       "FAIL: Degree hyperbolic sin";
 
-Print If == 88.412007823281300034068408422172 Coshd 1
+Print If == 1.0001523125762564 Coshd 1
       "PASS: Degree hyperbolic cos"
 else
       "FAIL: Degree hyperbolic cos";
 
-Print If == 0 Tanhd 0
+Print If == 0.17278206351636377 Tanhd 10
       "PASS: Degree hyperbolic tan"
 else
       "FAIL: Degree hyperbolic tan";
 
-Print If == 0 Sinh 0
+Print If == 74.20321057778875 Sinh 5
       "PASS: Radian hyperbolic sin"
 else
       "FAIL: Radian hyperbolic sin";
 
-Print If == 1 Cosh 0
+Print If == 74.20994852478785 Cosh 5
       "PASS: Radian hyperbolic cos"
 else
       "FAIL: Radian hyperbolic cos";
 
-Print If == 0 Tanh 0
+Print If == Tanh 8 / Cosh 8 Sinh 8
       "PASS: Radian hyperbolic tan"
 else
       "FAIL: Radian hyperbolic tan";