I'm biased, but very fond of the open-access introductory textbooks used where I studied. The department was very much pure maths, but the intro classes were ac

I'm biased, but very fond of the open-access introductory textbooks used where I studied. The department was very much pure maths, but the intro classes were accessible to general liberal arts students. I think the texts are relatively unique in that they're very proof oriented, yet with a pedagogical style that doesn't assume the reader is a future graduate student. For calculus, three options to see if you like a particular author's style of explanation: http://people.reed.edu/~mayer/math111.html/math111.pdf http://people.reed.edu/~mayer/math111.html/math111.pdf - the most pedagogical http://people.reed.edu/~mayer/math111.html/math111.pdf http://people.reed.edu/~mayer/math111.html/math111.pdf - the most beautiful https://people.reed.edu/~jerry/111/calc.pdf https://people.reed.edu/~jerry/111/calc.pdf - the most technical For introduction to mathematical analysis and proof: http://people.reed.edu/~mayer/math112.html/math112.pdf http://people.reed.edu/~mayer/math112.html/math112.pdf For multivariable calculus: https://www.stat.rice.edu/~dobelman/notes_papers/math/calculus.MV.pdf https://www.stat.rice.edu/~dobelman/notes_papers/math/calcul... [1] For linear algebra, we used the relatively standard Friedberg Insel and Spence [2], but I hear good things about https://hefferon.net/linearalgebra/ https://hefferon.net/linearalgebra/. [1] Link is off university domain, since apparently it was at some point turned into a bit more hardcore textbook oriented towards those going onto graduate studies in mathematics. If curious: https://www.amazon.com/Calculus-Analysis-Euclidean-Undergraduate-Mathematics/dp/3319841300 https://www.amazon.com/Calculus-Analysis-Euclidean-Undergrad... [2] https://www.amazon.com/Linear-Algebra-4th-Stephen-Friedberg/dp/0130084514 https://www.amazon.com/Linear-Algebra-4th-Stephen-Friedberg/...