How to find the root value of h in a differential equation?

How can I find the value h(real form and imagnery form) in this differential equation? My coding started with this.

syms E(h)
E(h)=((8*10e-6)*h)/((pi)*(8.854e-12)*(16+h^2)*(32+h^2)^1/2)
Df=diff(E,h)

Answer 1

[Alan Stevens]

Try adding the line

h = vpasolve(Df(h)==0,h)

[wyeen chow]

Thanks Alan, it works !!