diff --git a/man3/ctan.3 b/man3/ctan.3
index b479fea5b..60b2b065d 100644
--- a/man3/ctan.3
+++ b/man3/ctan.3
@@ -15,7 +15,8 @@ ctan, ctanf, ctanl \- complex tangent function
 .sp
 Link with \-lm.
 .SH DESCRIPTION
-The complex tangent function ctan(z) is defined as ccos(z)/csin(z).
+The complex tangent function ctan(z) is defined mathematically as
+csin(z) / ccos(z).
 .SH "CONFORMING TO"
 C99
 .SH "SEE ALSO"
diff --git a/man3/ctanh.3 b/man3/ctanh.3
index 631092020..c457ce245 100644
--- a/man3/ctanh.3
+++ b/man3/ctanh.3
@@ -15,8 +15,8 @@ ctanh, ctanhf, ctanhl \- complex hyperbolic tangent
 .sp
 Link with \-lm.
 .SH DESCRIPTION
-The complex hyperbolic tangent function tanh(z) is defined as
-cosh(z)/sinh(z).
+The complex hyperbolic tangent function tanh(z) is defined
+mathematically as sinh(z) / cosh(z).
 .SH "CONFORMING TO"
 C99
 .SH "SEE ALSO"