G(x) is odd function g(MAX)+g(min)=0.

You can also do it by taking derivatives.

The zero condition of the derivative f '(x)=0 can be simplified to the equation tanx = 2x/(x 2+ 1).

The left and right functions are odd function, so the zero point is symmetrical about the origin, so the zero point of g(x) is also symmetrical about the origin.

G (maximum) =M

Grams (minutes) =-meters

F (maximum) +f (minimum) =( 1+M)+( 1-M)=2.