There is a quadratic function going through (-2,1), (-1,2), (0,1). Write an equation for the graphed function f.

Please directly answer the question and provide the final value, e.g., 1, 2.5, 300.
Question: There is a quadratic function going through (-2,1), (-1,2), (0,1). Write an equation for the graphed function f.

Please first conduct reasoning, and then answer the question and provide the final value, e.g., 1, 2.5, 300, at the end.
Question: There is a quadratic function going through (-2,1), (-1,2), (0,1). Write an equation for the graphed function f.
