MATLAB具有求解函数极值以及函数图像的功能，简单举一个例子。

求解上述函数极值与图像：

1.驻点求解

syms x

>> y = (3*x^2 + 4*x +4)/(x^2 + x + 1);

>> dy = diff(y);

>> xz = solve(dy)

xz =

-2

0

2.驻点处二阶导数的正负情况

2y = diff(y,2);

>> z1 = limit(d2y,x,0)

z1 =

-2

>> z2 = limit(d2y,x,-2)

z2 =

3.极值求解

y1 = limit(y,x,0)

y1 =

4

>> y2 = limit(y,x,-2)

y2 =

8/3

4.函数图像

ezplot(y)

>> grid