derivative!! 10pts!!!
2009-10-03 11:28 pm
If A,B,C are functions of time related by A^2 = B^3 C^4, and B(7)=3 , C(7) =2 , A'(7) =5, and C'(-4), find B'(7).
回答 (1)
2009-10-04 3:07 am
✔ 最佳答案
A2 = B3C4[A(7)]2 = [B(7)]3[C(7)]4 = (3)3(2)4 = 432
A(7) = +- 12sqrt3
Differentiate both sides with respect to t
2AA' = 3B2B'C4 + 4B3C3C'
Put t = 7,
If A(7) = 12sqrt3, B'(7) = 8 + (5/18)sqrt3
If A(7) = -12sqrt3, B'(7) = 8 - (5/18)sqrt3
參考: Physics king
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