Knowledge atrophy is real. I've even talked to math PhDs who have forgotten areas of math they have definitely learned and excelled at but hadn't been using actively.
But I think your brain still subconsciously possesses knowledge of these supposed forgotten math skills. This is the reason why relearning these concepts will take way less time than learning them the first time. So I think just don't be afraid to relearn it.
But I think your brain still subconsciously possesses knowledge of these supposed forgotten math skills. This is the reason why relearning these concepts will take way less time than learning them the first time. So I think just don't be afraid to relearn it.