作者Honor1984 (希望愿望成真)
看板trans_math
标题Re: [微分]
时间Sat Nov 8 02:03:11 2008
※ 引述《Qmmm (．．Ｑ3Ｍ．．)》之铭言：
: x (n)
: f(x) = e * sinx , 求 f (x) = ?
: 这题不能用莱不泥滋吧？请教用什麽方法？谢谢!
f' = exp(x)sinx + exp(x)cosx = exp(x)[sinx + cosx]
= exp(x)[√2][sin(x+π/4)]
f' = √2 exp(x) [sin(x+π/4)]
=>f'' = exp(x)[√2]^2[sin(x+2*π/4)]
(n)
=>f = exp(x)[√2]^n[sin(x+n*π/4)]
自己微分一两次就会知道计算过程几乎相同
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1F：推 Qmmm:谢谢! 140.112.128.93 11/08 16:20