S_1(n)=(¦²[k=0 to n](z^k/k!))¡¦(¦²[k=0 to n](w^k/k!))=(1+z+z^2/2!+z^3/3!+¡Ä+z^n/n!)¡¦(1+w+w^2/2!+w^3/3!+¡Ä+w^n/n!)
S_2(n)=(¦²[k=0 to n]((z+w)^k/k!))=1+(z+w)+(z+w)^2/2!+(z+w)^3/3!+¡Ä+(z+w)^n/n!
(1+z+z^2/2!+¡Ä+z^j/j!+¡Ä)(1+w+w^2/2!+¡Ä+w^k/k!+¡Ä¡Ë =¦²[j=0 to ¡ç, k=0 to ¡ç] z^j¡¦w^k/j!k! =¦²[j=0 to ¡ç, k=0 to ¡ç] z^j¡¦w^k¡¦(j+k)!/j!k!(j+k)! =¦²[j=0 to ¡ç, k=0 to ¡ç] z^j¡¦w^k¡¦(j+k)!/(j+k-k)!k!(j+k)! =¦²[j=0 to ¡ç, k=0 to ¡ç] z^j¡¦w^k¡¦(j+k)_C_k / (j+k)! =¦²[n=0 to ¡ç] (z+w)^n/n!=1+(z+w)+(z+w)^2/2!+¡Ä+(z+w)^n/n!+¡Ä
=¦²(r=0 to n)z^(n-r)/(n-r)!¡ßw^r/r! =¦²(r=0 to n){z^(n-r)/w^r}/{(n-r)!r!} =1/n!¡ß¦²(r=0 to n)n!/{(n-r)!r!}¡ß{z^(n-r)w^r} =1/n!¡ßn_C_r {z^(n-r)w^r} =(z+w)^n/n!
¤è¤Ã¤Æ £Ð¡á¦²(n=0 to ¡ç)(z+w)^n/n! =(z+w)^0/0!+(z+w)^1/1!+(z+w)^2/2!+¡Ä ¡¡¡áe^(z+w)