Maths (Average num)
2008-09-04 10:59 pm
A tree of height y meters has, on average, B branches, where B = y - 6. Each branch has, on average, n leaves where n = 7B2 - B. Find the average number of leaves of a tree as a function of height.
回答 (2)
2008-09-05 1:23 am
✔ 最佳答案
number of leaves of a tree=number of branches x number of leaves in each branch
therefore
the average number of leaves of a tree
=average B branches x average n leaves in each branch
=Bn
=B(7B^2-B)
=B^2(7B-1), since B=y-6
=(y-6)^2[7(y-6)-1]
=(y-6)^2(7y-43)
=(y^2-12y+36)(7y-43)
=7y^3-127y^2+768y-1548
2008-09-04 11:22 pm
Average number of leave of a tree
= 7B2 - B
= 7(y - 6)2 - (y - 6)
= 7(y2 - 12y + 36) - (y - 6)
= 7y2 - 84y + 252 - y + 6
= 7y2 - 85y + 258
=
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