Suppose That $f ( x , y ) = x ^ { 2 } + 2 y ^ { 2 } - x$

Essay

Suppose that $f ( x , y ) = x ^ { 2 } + 2 y ^ { 2 } - x$ Find the minimum value of the function f when (x,y)is constrained to lie on or inside the triangle with vertices (0,-2), (0,1), and (1,-2).Give your answer to 4 decimal places.