# Functions of Several Variables f:R2→Rf: R^2 \to Rf:R2→R or f:R3→Rf: R^3 \to Rf:R3→R (1) Domain (2) Range (3) Graph (4) Level curves (等高線) or Surfaces. # Limits and Continuity Given ϵ>0,∃δ>0\epsilon > 0,\exists \delta > 0ϵ>0,∃δ>0 such that...
# Sequences A sequence is a function whose domain is NNN. (NNN is the set of all positive integers.) In notation, we write f(n)=anf(n) = a_nf(n)=an. # Theorem limx→∞f(x)=L,x∈R⇒limn→∞f(n)=L,n∈Nlim_{x \to \infty}f(x) = L, x \in R \Rightarrow lim_{n \to \infty}f(n) = L,n \in...