without a doubt: Calculus in a single variable with Robert Ghrist https://www.coursera.org/learn/single-variable-calculus https://www.coursera.org/learn/single-

without a doubt: Calculus in a single variable with Robert Ghrist https://www.coursera.org/learn/single-variable-calculus https://www.coursera.org/learn/single-variable-calculus for lots of people here it'll revisit some material you learnt at school but it does go further and the materials are fantastic and the exam at the end is no pushover either.