Mary Boas wrote one of my fav books targeting folks in the physical sciences: https://www.amazon.com/Mathematical-Methods-Physical-Science...

I'd say if you have a basic understanding of calculus (derivatives and integrals), you could get though Griffiths' books with another companion book, like what my college used: https://www.amazon.com/Mathematical-Methods-Physical-Science...

I'm still upset that my copies of Griffiths' texts were stolen my senior year of college...

this is another in the long line of math methods books that plague/bewilder/frustrate physics undergrads

standard: https://www.amazon.com/Mathematical-Methods-Physicists-Seven...

gentler: https://www.amazon.com/Mathematical-Methods-Physical-Science...

another recent addition: https://www.amazon.com/Mathematical-Tools-Physics-Dover-Book...

"purer" than the rest: https://www.amazon.com/Mathematical-Physics-Chicago-Lectures...

"more fun" than the rest: https://www.amazon.com/Geometry-Physics-Introduction-Theodor...

this pair is probably the most rigorous and difficult of the bunch (at least from what i remember):

https://www.amazon.com/Classical-Mathematical-Physics-Dynami...

https://www.amazon.com/Quantum-Mathematical-Physics-Walter-T...

and the grand-daddy of them all

https://www.amazon.com/Methods-Theoretical-Physics-Internati...

Mary L Boas "Mathematical Methods in the Physical Sciences" [1] has absolutely been my favorite and most-used maths text in the 9 years since graduating uni. It's like a reference manual of just about all the non-CS (i.e. continuous/non-discrete) mathematical techniques required in my career. Highly accessible. It's a little too terse in places but I prefer this style of presentation over the insane long-form verbiage in other books I've since discarded which can make even simple topics seem overwhelming: the "Boas" book gets right to the point.

Edit: Calling it a mini-TAOCP of most of the maths needed for physics/EE work might be a bit of a stretch, but I've yet to see another maths text that does better as a highly readable, self-contained and compact reference.

Edit2: I moved house once and thought I'd lost my copy from university. I eventually found it, and yes, I have two copies... It's that important to me for brushing off the things I've forgotten :)

[1] http://www.amazon.com/Mathematical-Methods-Physical-Sciences...