设y=arctan根号(x^2-1)-lnx/根号(x^2-1)求dy

>> syms x; y=atan((x^2-1)^(1/2))-log(x)/((x^2-1)^(1/2))
y =
atan((x^2 - 1)^(1/2)) - log(x)/(x^2 - 1)^(1/2)
>> diff(y)
ans =
(x*log(x))/(x^2 - 1)^(3/2)
可见答案是对的.
【MATLAB里log(x)表示ln(x),我们习惯的lg(x)用log10(x)表示,以其它数为底的对数用“log(x)”来表示】