Update 17.2.md

docs/Chap17/17.2.md

@@ -13,7 +13,7 @@ Since we have the size of the stack never exceed $k$, and there are always $k$ o
 
 > Redo Exercise 17.1-3 using an accounting method of analysis.
 
-Let $c_i =$ csot of $i$th operation.
+Let $c_i =$ cost of $i$th operation.
 
 $$
 c_i =
@@ -23,7 +23,7 @@ i & \text{if $i$ is an exact power of $2$}, \\\\
 \end{cases}
 $$
 
-Charge each operation $3$ (amotized cost $\hat c_i$).
+Charge $3$ (amortized cost $\hat c_i$) for each operation.
 
 - If $i$ is not an exact power of $2$, pay $\$1$, and store $\$2$ as credit.
 - If $i$ is an exact power of $2$, pay $\$i$, using stored credit.