I've been using it very recently. Not for mathematics , but for programming. And while Claude Opus is much more likely to admit mistake ("You're absolutely correct!" instead of "That's fine") when I correct it, it does require correcting, and has been incapable at grasping complex problems. I can't trust it to produce correct code for complex problems, because when I did, the solution turned out to be wrong. Plausible looking, and certainly producing some results, but not the correct ones.

It has still been useful, because parts of the problem have been solved before, and in some cases it can accurately reproduce those parts, which has been massively helpful. And it can help me understand some aspects of the problem. But it can't solve it for me. It has shown that that's simply beyond its capabilities.