Quōmodo rēctē "derivative of f(x)" dīcere?

Question

I am currently struggling to figure out how to translate the following phrase:

[...] derivative of f(x) [...]

I had a couple of initial ideas, namely:

1. dēductīva [fūnctiō] dē f(x)
2. dēductīva [fūnctiō] fūnctiōnis de x
3. dēductīva [fūnctiō] fūnctiōnis f(x)

And while these are (IIRC) correct Latin phrases, I am unsure as to whether or not they are similar (or the same as) the ways in which authors in mathematics (e.g, Leonhard Euler, Isaac Newton, etc.) would have expressed it.

In short, what is the "proper/idiomatic" way in which the phrase "derivative of f(x)" should be translated?

Answer 1

My understanding is that our modern notation was invented by Leibniz, who used the term "differentia", abbreviated as d. Someone ought to look up Leibniz's mathematical writings, which are in Latin.

Some discussion here: https://hsm.stackexchange.com/questions/1914/use-of-h-in-the-newton-quotient/1917#1917

Answer 2

Wikipedia defines derivative as derivativum. So maybe derivativum de f(x) would do.

Now, according to Wiktionary, derivativum is the neuter, nominative, singular of the noun derivativus, from which the English derivative comes from. However, the mathematical derivative is a noun, not an adjective. So I think we could not just translate the declination of the adjective, and write something like derivativi f(x). However, if we decline it as other nouns ending in "-um", like somnium, then derivativi f(x) might be in fact correct.

PS: I'm just a beginner. Beware.