若f（x）=sinx/x,则df（√x）/dx=?

若f（x）=sinx/x,则df（√x）/dx=?

复合函数求导
d f(√x) /dx = f '(√x) * 1/(2√x)
f '(x) = (x cosx - sinx) / x^2
f '(√x)= (√x cos√x - sin√x) / x
d f(√x) /dx = (√x cos√x - sin√x) / (2 x √x)