Let p=(p_(1),p_(2),p_(3)) be a fixed vector in R^(3) and let S={(x,y,z) : z=x^(2)-y^(2)}
Define a map f:S->R as f(v)=||v-p||^(2). That is, f returns the square of
the distance from a point v in S to p. Show that f is a smooth function. (Hint: choose a surface patch \sigma for S^(2) and verify that f composed of \sigma is smooth)