Is given a function:

f(x)=x2 + px + q
Prove that:
f(x+1) + f(x-1)= 2+2 f(x)

2 answers

just plug in the values:

f(x+1) = (x+1)^2 + p(x+1) + q
f(x-1) = (x-1)^2 + p(x-1) + q

add them to get

2x^2 + 2 + 2px + 2q
2(x^2+px+q) + 2
2f(x) + 2
Steve thanks very much, may i have your email id so i can ask a question with integrals/limits which i cant write here