From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Mon, 18 Jul 2022 21:18:50 +0000 (-0600)
Subject: Show a formula.
X-Git-Tag: v9.5.0-rc1~1073^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F14146%2Fhead;p=dealii.git

Show a formula.
---

diff --git a/include/deal.II/base/symmetric_tensor.h b/include/deal.II/base/symmetric_tensor.h
index bd6c92434f..d69798c9a6 100644
--- a/include/deal.II/base/symmetric_tensor.h
+++ b/include/deal.II/base/symmetric_tensor.h
@@ -37,6 +37,10 @@ class SymmetricTensor;
 /**
  * Return a unit symmetric tensor of rank 2, i.e., the
  * $\text{dim}\times\text{dim}$ identity matrix $\mathbf I$.
+ * For example, if `dim==2`, then this matrix has the form
+ * @f[
+ *   I_{2\times 2} = \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}.
+ * @f]
  *
  * @relatesalso SymmetricTensor
  */