diff --git a/source/calculus/source/02-DF/02.ptx b/source/calculus/source/02-DF/02.ptx
index 8c04d3fb..953e61d4 100644
--- a/source/calculus/source/02-DF/02.ptx
+++ b/source/calculus/source/02-DF/02.ptx
@@ -281,7 +281,7 @@ The second derivative is the derivative of the derivative. It encodes informatio
     <subsection>
         <title>Videos</title>
         <figure>
-            <video xml:id="video-DF2" youtube="4UErodf99UE"/>
+            <video xml:id="video-DF2" youtube="_e4F_lKOUII"/>
             <caption>Video for DF2</caption>
         </figure>
     </subsection> 
@@ -292,4 +292,4 @@ The second derivative is the derivative of the derivative. It encodes informatio
             Exercises available at <url href="https://tbil.org/calculus/preview/exercises/#/bank/DF2/"/>
         </p>
     </subsection>
-</section>
\ No newline at end of file
+</section>
diff --git a/source/calculus/source/02-DF/05.ptx b/source/calculus/source/02-DF/05.ptx
index c2fbd774..2812156d 100644
--- a/source/calculus/source/02-DF/05.ptx
+++ b/source/calculus/source/02-DF/05.ptx
@@ -286,7 +286,7 @@
     <subsection>
         <title>Videos</title>
         <figure>
-            <video xml:id="video-DF5" youtube="qGK9bgyTQH8"/>
+            <video xml:id="video-DF5" youtube="pLMcL7y_90Y"/>
             <caption>Video for DF5</caption>
         </figure>
     </subsection> 
@@ -298,4 +298,4 @@
         </p>
     </subsection>
 
-</section>
\ No newline at end of file
+</section>