I try to get the step-by-step solution for D[E^x, x] as follows:
WolframAlpha["D[E^x, x]", IncludePods -> "Input",
AppearanceElements -> {"Pods"}, PodStates -> {"Input__Show steps"}]
The result is given below:
![enter image description here](https://community.wolfram.com//c/portal/getImageAttachment?filename=1195Selection_185.png&userId=2470387)
As you can see, this proof method is clearly trapped in the logic of circular argumentation, and therefore invalid.
Regards,
Zhao