"Calculus Made Easy" by Silvanus P. Thompson, now in public domain. https://calculusmadeeasy.org/ https://calculusmadeeasy.org/ The book is worth a peek just

"Calculus Made Easy" by Silvanus P. Thompson, now in public domain. https://calculusmadeeasy.org/ https://calculusmadeeasy.org/ The book is worth a peek just for this one chapter: https://calculusmadeeasy.org/1.html https://calculusmadeeasy.org/1.html