I want to learn maths for artificial intelligence. I heard that main areas of mathematics for AI are Multivariable Calculus, Linear Algebra, Probability and Statistics and Discrete Mathematics. But what level of these subjects do I need?
For example the easy level is like Calculus of Gilbert Strang and 18.01 Calculus from MIT Open Course Ware. The hard level is Apostol's or Spivak's Calculus.
Do I need easy level of maths or hard level to be good at artificial intelligence and its areas (machine learning, pattern recognition).