I do not know how to do (a) part only, thanks for your teaching.?
回答 (1)
2018-10-29 5:25 pm
✔ 最佳答案
set C = a r^3 + b r^2r=1, 200 = a + b ...(1)
r=2, 1120 = 8 a + 4 b ...(2)
(2)-(1)*4
320 = 4 a ---> a = 80 ---> b = 120
C = 80 r^3 + 120 r^2 ......Ans
收錄日期: 2021-04-24 01:16:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20181029025633AAEqyN8