Найдите наибольшее значение функции y = 4x2-13x+5ln x-8 на отрезке [1/14 до 15/14] Ответ -17 ?
y = 4x^2-13x+5ln x-8
y' = 8x-13+5/x = 0
8x-13+5/x = 0 |*x
8x^2-13x+5 = 0
D = 169 - 160 = 9
x_1 = (13+3)/16 = 1
x_2 = 10/16 = 5/8
y(1) = 4-13+5ln 1-8 = -17
y(5/8) = 4(5/8)^2-13(5/8)+5ln 5/8-8 = -233/16 -5log(8/5) > - 17
Ответ: -17
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y = 4x^2-13x+5ln x-8
y' = 8x-13+5/x = 0
8x-13+5/x = 0 |*x
8x^2-13x+5 = 0
D = 169 - 160 = 9
x_1 = (13+3)/16 = 1
x_2 = 10/16 = 5/8
y(1) = 4-13+5ln 1-8 = -17
y(5/8) = 4(5/8)^2-13(5/8)+5ln 5/8-8 = -233/16 -5log(8/5) > - 17
Ответ: -17