
Yefim S. answered 07/15/20
Math Tutor with Experience
Thisv function continius on interval [0, 25] and differentiable on interval (0,25). Now, f(0) = f(25) = 0.
So, by rolls theorem exist point 0<, x < 25 where f'(x) = 0. Let find this point x: f'(x) = 1/2x-1/2 - 1/5 = 0;
1/x1/2 = 2/5; x1/2 = 5/2, x = 25/4 = 6.25.
So, f'(6.25) = 0 and 0< 6.25 < 25