Charles K. Chui, Tian-Xiao He, Bivariate $C^1$ Quadratic Finite Elements and Vertex Splines, Mathematics of Computation, Vol. 54, No. 189 (Jan., 1990), pp. 169-187 ...

Revise how to recognise and determine the equation of a quadratic function from its graph. BBC Bitesize Scotland revision for SQA National 5 Maths.