[理工] [離散]
95師大資工
Please find the coefficient of x^15 term in ( x^3 - 5x )/( 1 - x )^3.
自己的算法是將x^3提出式子整理成x^3(1-5/x^2)/(1-x)^3求x^15的係數，看成(1-5/x^2)/(1-x)^3求x^12的係數，只會求1/(1-x)^3…寫出(3+12-1,12)之後，(1-5/x^2)這部分不知道該怎麼處理…
解答是給C(14,12)-5C(16,14)
請問-5C(16,14)是什麼意思?
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