Differentiation by first principles is as followed:
$$y'=\lim_{h\rightarrow 0}\dfrac {f\left( x+h\right) -f\left( x\right) }{h}$$
So, assuming that ##y= e^{x},## can we prove, using first principle, that:
$$\dfrac{dy}{dx}\left( e^{x}\right) =e^x$$
Or is there other methods that are...