Hi, I'm an engineering major. I began my college years with a substandard understanding of math. I am now taking Calculus 3 and Differential Equations this semester. I have made average grades up to this point and I am actually improving in that respect. Hopefully I'll come out with an A and B this semester, respectively. My question is, are there any good sources of higher math learning that are audio based? I'd like to review what I've learned in my past calculus classes as well as cover the material I'm learning now. (I realize that this is not higher math to a mathematician, but to a lowly engineer it is.) I ask this because I spend a great deal of time consuming audio entertainment and edification throughout the week. I realize that this won't be ideal for covering the nitty gritty specifics of solving equations. However since I still don't feel like I fully grasped all that was taught I'd like an easy way to think over it.