diff --git a/04-Engineering_Math.pdf b/04-Engineering_Math.pdf
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Binary files a/04-Engineering_Math.pdf and b/04-Engineering_Math.pdf differ
diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -1,4 +1,5 @@
 # math
 
 Limit = Approach
+
 Derivative = Change