# interesting problem

Let f(x) = ax^2 + bx + c where a; b; c are real numbers. Suppose f(-1),f(0), f(1) belong to [-1,1]. Prove that |f(x)| ·<= 3/2 for all x belonging to [-1,1].

Note by Pranav Chakravarthy
5 years, 1 month ago

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what does " belong to [1;1] " means.....it does not indicate any interval .....does this means the set of value {1} only?......again why did u write two times f(1) .....?!?...not understanding...

- 5 years, 1 month ago

oops sorry the other one is f(-1) and the values of f(1),f(0),f(-1) lies in the interval [-1,1]

- 5 years, 1 month ago

i think....its...[-1,1]...and f(-1),f(0),f(1)........:)

- 5 years, 1 month ago

silly question

- 5 years, 1 month ago

why,...?

- 5 years, 1 month ago