For the following expression,

b'[x y/z]+z b''[x y/z]

I want to replace the argument of b such that the above expression becomes

b'[z]+z b''[z]

How can I do that ?

  • 1
    $\begingroup$ Note that if xy is intended to be the product of x and y then it should be entered as either x y (implicit product with a space) or as x*y (explicit product). $\endgroup$ – Bob Hanlon May 30 '16 at 14:21

As a general case where you want to replace all the arguments,

(b'[x y/z] + z b''[x y/z]) /. Derivative[n_][b_][x_] :> Derivative[n][b][z]

z b''(z)+b'(z)

No matter what was your previous argument, it will be replaced by z.

b'[xy/z] + z b''[xy/z] /. {xy/z -> z}

gives me an output of

b'[z]+z b''[z]

Is that what you meant?


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.