請大師師兄們幫忙牙
In the figure,a right cylindrical solid with the height of x cm(where x<10) and the volume of y cm^3 is inscribed in a hollow sphere with a radius of 10cm.
a) Prove that y= 100TTx - TT/4 (x^3).
b) If the volume of the cylindrical solid is 198TT cm^3, find its height.
圖片參考：http://imgcld.yimg.com/8/n/HA00714275/o/701203180010613873450100.jpg
S4 polynomial
2012-03-18 12:22 pm
回答 (3)
2012-03-18 2:07 pm
✔ 最佳答案
圖片參考：http://imgcld.yimg.com/8/n/HA01029403/o/701203180010613873450111.jpg
圖片參考：http://imgcld.yimg.com/8/n/HA01029403/o/701203180010613873450112.jpg
有問題的話再提出吧。
2012-03-18 23:49:16 補充：
rick:
唔好咁講~~
簡單黎講就係用畢氏定理。
如果可以既話,你比你個email我,我畫幅圖向你解釋
咁比較清楚,就咁講好難表達。
參考: 自己
2012-03-19 2:32 am
可能我太蠢, 掁文兄的 a) step1 我不明,可以加以引導麻?
2012-03-18 6:53 pm
(a) Using Pythagoras' Theorem,
r^2 + (x/2)^2 = 10^2
r^2 = 100 - x^2/4
The volume of the cylinder
= πr^2x
= π(100 - x^2/4)x
= 100πx - πx^3/4
(b) 100πx - πx^3/4 = 198π
100x - x^3/4 = 198
x^3 - 400x + 792 = 0
x = 2
The height of the cylinder is 2 cm
r^2 + (x/2)^2 = 10^2
r^2 = 100 - x^2/4
The volume of the cylinder
= πr^2x
= π(100 - x^2/4)x
= 100πx - πx^3/4
(b) 100πx - πx^3/4 = 198π
100x - x^3/4 = 198
x^3 - 400x + 792 = 0
x = 2
The height of the cylinder is 2 cm
收錄日期: 2021-04-16 15:25:53
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120318000051KK00106