Fix typo

Fix typos introduces more

pages/CSE442T/CSE442T_L13.md

@@ -16,7 +16,7 @@ $$
 Pr[x\gets \{0,1\}^n;y=f(x);A(1^n,y)=h(x)]\leq \frac{1}{2}+\epsilon(n)
 $$
 
-Idea: $f:\{0,1\}^n\to \{0,1\}^*$ is a one-way function.
+Ideas: $f:\{0,1\}^n\to \{0,1\}^*$ is a one-way function.
 
 Given $y=f(x)$, it is hard to recover $x$. A cannot produce all of $x$ but can know some bits of $x$.
 
@@ -46,7 +46,7 @@ $\langle x,1^n\rangle=x_1+x_2+\cdots +x_n\mod 2$
 
 $\langle x,0^{n-1}1\rangle=x_ n$
 
-Idea of proof:
+Ideas of proof:
 
 If A could reliably find $\langle x,1^n\rangle$, with $r$ being completely random, then it could find $x$ too often.