What is the turning point on the curve f(x) = 2x^2 - 2x + 4

df/dx = 4x - 2

turning point when differential = 0 

==>

4x = 2 hence;  x = 0.5

When x = 0.5 f(x) is equal to (substitute) 3.5

hence the turning point is at (0.5,3.5)