1 files changed, 29 insertions, 0 deletions
diff --git a/src/math/tan.c b/src/math/tan.c
new file mode 100644
index 00000000..16d83d78
--- /dev/null
+++ b/src/math/tan.c
@@ -0,0 +1,29 @@
+# define TGSOURCE "tan.c"
+#include <math.h>
+#include "nonstd/tgmath.h"
+#include "errno.h"
+
+/** tangent **/
+TYPE TGFN(tan)(TYPE x)
+{
+	if (0) {
+		errno = ERANGE; /* The result cannot be represented */
+		/* RETURN_FAILURE(CONSTANT(HUGE_VAL), A range error occurred); */
+		return TGHUGE;
+	}
+
+	/* RETURN_SUCCESS(the tangent of ARGUMENT(x)); */
+	return TGFN(sin)(x) / TGFN(cos)(x);
+}
+
+/***
+compute the tanget of ARGUMENT(x), in radians.
+***/
+
+/*
+IMPLEMENTATION(The value returned on a domain error, CONSTANT(HUGE_VAL))
+LINK(m)
+*/
+/*
+STDC(1)
+*/