Ask Uncle Colin is a chance to ask your burning, possibly embarrassing, maths questions — and to show off your skills at coming up with clever acronyms. Send your questions to email@example.com and Uncle Colin will do what he can.
Dear Uncle Colin,
I don’t understand why the normal gradient is the negative reciprocal of the tangent gradient. What’s the logic there?
— Pythagoras Is Blinding You To What’s Obvious
Hi, PIBYTWO, and thanks for your message!
My favourite way to think about perpendicular gradients is to imagine a line going across a chessboard. Let’s say…
Continue reading at: