http://upload.lsforum.net/users/public/f12640Q18p132.gif
The figure shows a right circular cylinder with AC being a diameter of its upper face. AB and CD are two vertical lines on the curved surface. A curve is drawn as shown on the surface of the cylinder from B to C. If its shortest length is 6√(π^2 +1). Find the curved surface area of the cylinder.
Ans.: 24π cm^2
請問各位可詳細解釋中間的步驟嗎?
THZ!>,<
1條Circular cylinder問題
2013-04-04 4:29 pm
回答 (1)
2013-04-04 5:29 pm
✔ 最佳答案
圖片參考：http://i1295.photobucket.com/albums/b635/ToineCheung/01_zps92ef9956.jpg
基本上你可以將它拆做一個三角形，斜邊正是那條曲線的長度，高是 6cm，底是1.5個圓周（因為圖內它圍了1.5個圈） [6√(π² +1)]² = [(3/2)(2πr)]² + 6² (Pyth. Theorem) 36π² + 36 = 9π²r² + 36 36π² = 9π²r² r = 2cm The curved surface area = πr²h = π(4)(6) = 24π cm²
收錄日期: 2021-04-23 21:45:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130404000051KK00075