Given f(x) = (2x2 + 1)/(x3 + 2x).

Step 1: State the definition of the derivative using the first principle.
The derivative of a function $f(x)$ from the first principle is given by:

$$f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}$$

Given $f(x) = \frac{2x^2 + 1}{x^3 + 2x}$.

Step 2: Substitute $f(x+h)$ and $f(x)$ into the formula.

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