# Goes deeper

Something like $$\frac{a}{b}$$, split by $$-$$, we call $$a$$ `Molecular`, $$b$$ `Denominator`.

$$
\begin{align*}
f(x) &= x^2
\\ \\
&\Downarrow \text{Take derivative of the previous formula}
\\ \\
f^\prime(x) &= 2x    &(x^2)^\prime &= 2x
\\ \\
&\Downarrow \text{Take derivative of the previous formula}
\\ \\
f^{\prime \prime}(x) &= 2    &(2x)^\prime &= 2
\end{align*}
$$

We say $$f^\prime(x)$$ is the first derivative of $$f(x)$$, $$f^{\prime \prime}(x)$$ is the second derivative of $$f(x)$$. You can keep doing this by changing the number before `derivative`, for example, 3 derivative of ...

