數學 疊加法求公式解 幫幫忙?

2017-03-25 10:14 pm
若(2x−3)5 =ax5+bx4+cx3+dx2+ex+ f ,求b+c+d+e的值為?

回答 (4)

2017-03-26 3:33 am
✔ 最佳答案
b + c+ d+ e = -c(5,1)*2^4*3 + c(5,2)*2^3*3^2 - c(5,3)2^2*3^3 + c(5,4)2*3^4

= -240 +720 - 1080 + 810

= 1530 - 1320

= 210

= Answer
2017-03-26 9:16 pm
a=2^5=32
x=0 則f=(-3)^5=-243
x=1 則-1= a+b+c+d+e+f
b+c+d+e=210
2017-03-26 8:18 am
若(2x−3)^5 =ax^5+bx^4+cx^3+dx^2+ex+ f ,求b+c+d+e的值為?

b+c+d+e = (a+b+c+d+e+f) - (a+f)

(2*1-3)^5 = a+b+c+d+e+f = -1
(2x-3)^5 = 2^5 x5 +... + (-3)^5
a = 2^5 = 32, f = (-3)^5 = -243
故 b+c+d+e = (-1) - [32+(-243)] = 210
2017-03-25 11:23 pm
(2X-3)^5=C(5,0)(2X)^5+C(5,1)(2X)^4(-3)+C(5,2)(2X)^3(-3)^2+C(5,3)(2X)^2(-3)^3+C(5,4)(2X)(-3)^4+C(5,5)(-3)^5=32X^5-240X^4+720X^3-1080X^2+810X-243
所以B+C+D+E=-240+720-1080+810-243=-13


收錄日期: 2021-05-01 15:28:01
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20170325141426AA6NdV6

檢視 Wayback Machine 備份