extreme ln(x)+1/x

解答

极值点

ln (x) + \frac{1}{x}

极小值 (1, 1)

求解步骤

f^{'} (x) = \frac{1}{x} - \frac{1}{x ^{2}}

Find intervals:

递减

: 0 < x < 1,

递增

: 1 < x < \infty

将

x = 1

代入

ln (x) + \frac{1}{x} : 1

极小值 (1, 1)

e x t re m e f (x) = \frac{x ^{2}}{( x - 4 ) ^{2}}

e x t re m e f (x, y) = 4 x^{2} + 4 y^{2} + x^{4} + y^{4} - 6 x^{2} y^{2}

e x t re m e f (x, y) = x^{3} + \frac{3}{2} y^{2} - 3 x y - 124

e x t re m e 3 x^{4} - 4 x^{3} + 1

e x t re m e f (x, y) = 8 x^{4} + y^{2} - 16 x y