Question

a的x次方 求导过程不懂

怎样由1变到2的求过程

Answer 1

复合函数中的链式法则
ƒ(g(x))对x求导得ƒ'(g(x)) • g'(x)
或dy/dx = dy/du • du/dx
在这里，e^(xlna)，令ƒ(u) = e^u，u = g(x) = xlna
ƒ'(u) = e^u，g'(x) = lna
则[ƒ(g(x))]' = ƒ'(u) • g'(x) = e^u • lna = e^(xlna) • lna = a^x • lna
或
令y = e^u，u = xlna
则dy/du = e^u，du/dx = lna
所以dy/dx = dy/du • du/dx = e^u • lna = e^(xlna) • lna = a^x • lna

Answer 2

Answer 3

复合函数的求导，令t=xlna,（e∧(xlna)）'=(e∧t)’×t’=e∧t×t’