diff --git a/ggml.c b/ggml.c
index 3e721677a..009d5b398 100644
--- a/ggml.c
+++ b/ggml.c
@@ -11043,8 +11043,9 @@ static void ggml_compute_forward_rope_f32(
     const bool is_neox = mode & 2;
     const bool is_glm  = mode & 4;
 
-    // backward process uses derivative of cos and sin.
-    // derivative of cos is just cos, derivative of sin is -sin.
+    // backward process uses inverse rotation by cos and sin.
+    // cos and sin build a rotation matrix, where the inverse is the transpose.
+    // this essentially just switches the sign of sin.
     const float sin_sign = forward ? 1.0f : -1.0f;
 
     const int32_t * pos = (const int32_t *) src1->data;
@@ -11199,8 +11200,9 @@ static void ggml_compute_forward_rope_f16(
     const bool is_neox = mode & 2;
     const bool is_glm  = mode & 4;
 
-    // backward process uses derivative of cos and sin.
-    // derivative of cos is just cos, derivative of sin is -sin.
+    // backward process uses inverse rotation by cos and sin.
+    // cos and sin build a rotation matrix, where the inverse is the transpose.
+    // this essentially just switches the sign of sin.
     const float sin_sign = forward ? 1.0f : -1.0f;
 
     const int32_t * pos = (const int32_t *) src1->data;