[R] D function

[Erin Hodgess]

Dear R People:

Suppose I put in the following:

> w1 <- expression(2*x)
> v1 <- expression(x^2)

and I want to get the derivative of w1 * v1 with respect to x
> D(w1*v1,"x")
Error in w1 * v1 : non-numeric argument to binary operator


Is there a way around this, please?

Thanks in advance!

Sincerely,
Erin M. Hodgess, Ph.D.
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
One Main Street 
Houston, TX 77002
e-mail: hodgess at uhddx01.dt.uh.edu


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