It depends on what "pursuing ML/AI" means. I've written a recommendation engine with barely understanding linear algebra and a spam filter without knowing Bayes theorem. A programmer can work on ML systems without having a solid foundation in higher maths. However, if you want to develop your own solutions then you surely need the math.

I would recommend reading Toby Segaran's Programming Collective Intelligence: http://shop.oreilly.com/product/9780596529321.do