Is the notation for expressing the partial derivative for multivariable functions also valid for single variable functions?

Question

Pretty self explanatory question. I have seen the derivative of a function $f$, where $$f := f\left(x,y\right)$$ to be expressed as

$$f_{x}\left(x, y\right) = \frac{\partial}{\partial x}f\left(x, y\right)$$

Now would it be valid to apply this to a single variable function. i.e.

$$f := f\left(x\right)$$ $$f_{x}\left(x\right) = \frac{d}{dx}f\left(x\right)$$

Answer 1

Yes.

For a monovariate function, the partial derivative with respect to its argument is the normal derivative, so the same notation may be used.

Though more often we just use the usual $f^\prime$ notation.