Merge pull request #88 from snowch/claude/fix-bernoulli-rendering-mjFhe

Clarify binomial formula derivation in coin flip example

Author: snowch

chapter_07.md

@@ -579,7 +579,9 @@ Let's verify this works for our coin flip example (n=10, p=0.5):
 
 $$
 \begin{align}
-P(X=5) &= \binom{10}{5} (0.5)^5 (0.5)^5 \\
+P(X=5) &= \binom{10}{5} p^5 (1-p)^{10-5} \\
+&= \binom{10}{5} (0.5)^5 (1-0.5)^5 \\
+&= \binom{10}{5} (0.5)^5 (0.5)^5 \\
 &= 252 \times 0.03125 \times 0.03125 \\
 &\approx 0.246 \quad \checkmark
 \end{align}