I completely agree. I have Bell's book on the infinitesimal approach and it is infinitely (hah) more intuitive (hah again) than epsilon-delta limit foundations. It trades a heady second order logical statement for simple algebra.
There's also really no excuse not to use it anymore since category theory has provided some of the missing rigor. I think there's a reason that Leibniz et al essentially started with this basis.
It trades a heady second order logical statement for simple algebra.
Also, other comment here says they wish calculus were more visual. Newton-style proofs were actually geometric, and the proofs in the book are like that too. You build triangles etc. with infinitesimal sides, and the math works
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I completely agree. I have Bell's book on the infinitesimal approach and it is infinitely (hah) more intuitive (hah again) than epsilon-delta limit foundations. It trades a heady second order logical statement for simple algebra.
There's also really no excuse not to use it anymore since category theory has provided some of the missing rigor. I think there's a reason that Leibniz et al essentially started with this basis.
Also, other comment here says they wish calculus were more visual. Newton-style proofs were actually geometric, and the proofs in the book are like that too. You build triangles etc. with infinitesimal sides, and the math works