[english] start WoT practice essay

diff --git a/methods/stuff.md b/methods/stuff.md
index 1cbb98b3875a77ca838f5fb08ecdc955aedaa2a6..adbb286512fed3d4a61ce11188ba44829a41645e 100644 (file)
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@@ -53,3 +53,7 @@ $\log_a1 = 0$ and $\log_aa = 1$
 ## Inverse functions
 
 Inverse of $f: \mathbb{R} \rightarrow \mathbb{R}, f(x)=a^x$ is $f^{-1}: \mathbb{R}^+ \rightarrow \mathbb{R}, f^{-1}=log_ax$
+
+## Euler's number
+
+$$e= \lim_{n \rightarrow \infty} (1 + {1 \over n})^n$$