#60 · Functions & graphs · Class 12
Saddle Surface
The hyperbolic paraboloid z = k(x² − y²): it curves up in one direction and down in the other.
Saddle Surface📐 Formula
z = k(x² − y²); the origin is a saddle point (neither maximum nor minimum)
✏️ Worked example
k = 0.25: along x, z = 0.25x² rises; along y, z = −0.25y² falls.
🌍 Where it is used
Pringles crisps and some modern roofs.
❓ Quick check
The origin of z = x² − y² is a…