求dy/dx..................

2008-01-08 3:29 am
若 x =asin t 及 y =asin t 其中 a ﹑t ≠ 0 ,求dy/dx
更新1:

= = ....sor 打錯左 若 x =asin t 及 y =acos t 其中 a ﹑t ≠ 0 ,求dy/dx

回答 (3)

2008-01-08 4:13 am
✔ 最佳答案
Q: 若x = a sint 及 y = a cost, 其中 a, t ≠ 0, 求 dy/dx

Sol:

x = a sint

x² = a² sin²t

y = a cost

y² = a² cos²t

y² = a² ( 1 - sin²t )

y² = a² - a² sin²t

y² = a² - x²

y = √( a² - x² )

dy/dx = 1/2 * 1/√( a² - x² ) * ( - 2x )

dy/dx = - x/√( a² - x² )

Ans: dy/dx = - x/√( a² - x² )
參考: 數學小頭腦
2008-01-08 3:41 am
Is there any error in the question? Because in this case y = x and dy/dx will be 1.
2008-01-08 3:33 am
x =asin t 及 y =asin t

dx/dt = a cos t

dy/dt = a cos t

dy/dx = dy/dt x dt/dx = (a cos t) x [1/ ( a cos t)] = 1


收錄日期: 2021-05-01 17:26:46
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080107000051KK03116

檢視 Wayback Machine 備份