leio125

\[f(x)=\sum_{i=0}^{\n}{a_i x^i}, \ g(x)=\sum_{j=0}^n{b_jx^j\] \[(f+g)(x):=\sum_{i=j=1}^{n}{(a_i+b_j)x^i\] \[(f\cdot g)(x):=\sum_{h=0}^{n+n}{\sum_{i+j=h}{a_ib_jx^h}\] Rules are important, otherwise: \[x=x\] \[x^2=x^2\] \[x^2-x^2=x^2-x^2\] \[x(x-x)=(x+x)(x-x)\] \[x=x+x\] \[1=2\] Meglio avere regole no?