I never taught calculus and in fact found it daunting when I was learning it 20+ years ago, but I have to say I'm enjoying learning it again this time around (thanks to some very wonderful teachers on Youtube!) I'm keeping one step ahead of my student and so far things are working out well, until lately when I was doing the last homework assignment on curve sketching with first and second derivatives. I'll be posting my question in the forum this evening. I thank you all in advance for your very kind help!