Do You Think AI Will End Such Sites?

I think calculator sites will always be prevalent. I will always go to calculator over AI, it's just easier. i don't have time to type out equations to get an answer.

Even if AI would be capable of doing it in the future, I can't imagine a person explains a numerical calculus to AI or even show it.

Your should worry about Google or other stuff, even stock camera apps will do this calculations in the future maybe?

No, AI is good but not that good to do a lot of things will need to go more years in development accuracy is not 100% and they still training it a lot, many years in the future yes, is posible.