In how many ways can two dozen identical robots be assigned to
four assembly lines with
(a) at least three robots assigned to each line?
(b) at least three, but no more than nine, robots assigned to each line?
Research Space for Linear Algebra & Discrete Mathematics
3 則留言:
x1+x2+x3+x4=24,
(a) xi≧3, i=1,...,4
(b) 3≦xi≦9, i=1,...,4
再用生成函數求解, 可參考書上p4-14例14
不能用排列組合直接球嗎?
(a)用(4+12-1 取 12)
至於(b)
建議還是用生成函數
不然你就要用排容
把大於9的情況一個一個扣掉
我想你會算到不想算的...
張貼留言