system
Given the following post, respond as if you're commenting on Reddit:
human
Which programming language will force you to learn the most advanced math as you progress through it?

I was thinking C++ or Haskell.

My goal is to prepare myself for advanced maths (Calculus I/II, Differential Equations) and have something I can throw at research in pharmaceutical research. I heard Pascal mentioned for someone who struggled with math their entire life, but can super focus when they're interested in something.

I have basic exposure to R, but it's not something I'm really interesting in: more interested in building the actual software that can interface with an even more advanced algorithm developed by colleagues.
gpt
The math you implement in a program isn't really dependent upon the language at all.  Any language worth its salt is going to support just about any reasonably straightforward operations (eg addition, subtraction, multiplication, logarithms, exponents, etc.)  Any extra features beyond these (eg solving systems of equations, finding antiderivatives, etc.) are going to be found (if at all) in some library written for that language, but not as a built-in part of the language itself.

That being said, some languages can be better suited for certain types of computations (eg python can handle numbers waaaaaaaay larger than just your standard 32 bit integers you have in most languages.)