Dear Uncle Colin,

I’m told that $x^2 \tan(y) = 9$, for $0<y< \piby 2$. I have to show that $\dydx = \frac{-18x}{x^4+81}$, and that there’s a point of inflection at $x = 27^{1/4}$. Where do I even start!?

- I Might Plot Loci… I Can’t, It’s Tricky

Hi, IMPLICIT, and thanks for your message!

Hope that helps!

- Uncle Colin