Is there any way to do symbolic differentiation in Stata or Mata? i.e., deriv(x^2)=2x?
Related to this question: suppose I regress y on x and z and want to estimate the variance of x_hat/z_hat. Are there any commands that let you calculate the variance of this expression automatically? (I'd like to avoid calculating the first-order taylor expansion etc. myself, especially for more complicated expressions).
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