plotting f'(x) on a graph, then finding the y value at a point x, is what the description is saying.

In many countries, and in higher mathematics, this is standard terminology.
It is missing a comma, at worst:
'and a point to evaluate the equation_,_ as an integer.'

Go check out wolfram math world.

And I thought I had some unorthodox solution

When operations are able to be chained like this, it's always tempting to reduce the line count of a solution, especially when the potential exists to reduce it to just a single line. When we do that, though, we sacrifice an opportunity to communicate to maintenance developers the significance of intermediate operations.

Here, for example, the significance of the split('') operation is left undisclosed, which is to deduce the "digits" from the original number. Applying the "extract variable" refactor to describe that significance is important in production-quality code.

(I realize "production quality" isn't always the intent of the solutions's author, but my statement is for the benefit of those who might otherwise mistake this solution's "best practice" rating as an indicator of perfection.)

Yes, you can't compare arrays like that.

removed that testcase

I think the author meant Punctuation marks should be treated as if they are a part of the word in this kata.

Ok. The profanity filter has been requested, but it was rejected: https://github.com/Codewars/codewars.com/issues/1474

Also, profanity words aren't really abuse. You don't report that, you might filter it though. Something like the links I mentioned above are something better to report.

This website is full of profanity stuff, unfortunately :/

No, it's cuz I'm mainly good at math so I use artofproblemsolving.com. They have a resource called For The Win! and it has a report abuse page + language filter. CW could probably use the same code in here. Would help a lot.

I agree with you, but it's just that a lot of people don't care about cuss words.

It doesn't have to be a new user, I've seen power users do it too.

Yes, a report function would be useful though. Did you see the links I mentioned?

kinda ruins the point because most people need a fixed sol in test cases so it spoils it

Ok. But I found another one too:

https://www.codewars.com/kata/tortoise-racing/discuss/javascript

There's a 7 kyu saying 'D***, i was just happy to get it to work'

See this is why we need a filtering system. People can say cuss words as free as they please.