写出matlab代码?
题目不是很清楚，就挑清楚地做一下。
% By lyqmath
% DLUT School of Mathematical Sciences
% BLOG： blog.csdn/lyqmath
clc; close all; clear all;
syms x
y = sin(x)/x;
diff(y, x)
syms x
eq = x^2*sin(x);
int(eq, x)
t = linspace(-4*pi, 4*pi);
y = sin(t);
figure; plot(t, y);
结果：
ans =
cos(x)/x - sin(x)/x^2
ans =
2*x*sin(x) - cos(x)*(x^2 - 2)
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求各位大神帮忙编一下matlab程序
f = @(x) sum(x); % 目标函数
A=[-6,-4,-4,-2,-1,-1,0;0,-1,0,-2,-1,0,-1;0,0,-1,0,-1,-2,0]; % 线性约束
B = [-100,-100,-100];
lb=zeros(1,7); % 下限为0
ub=inf*ones(1,7); % 上限为无穷大
op = optimset('Algorithm','interior-point'); % 约束算法
x0 = 10*ones(1,7); % 假设初始值为每个变量都是10
[x,fval] = fmincon(f,x0,A,B,[],[],lb,ub,[],op) % 约束极值
Local minimum found that satisfies the constraints.
Optimization completed because the objective function is non-decreasing in
feasible directions, to within the default value of the function tolerance,
and constraints were satisfied to within the default value of the constraint tolerance.
x =
0.0000 0.0000 0.0000 33.3211 33.3579 33.3211 0.0000
fval =
100.0000
求高手帮忙编MATLAB程序
在Matlab下输入：edit，然后将下面两行百分号之间的内容，复制进去，保存
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function f=f31(x)
f=1./[(x-2).^2+0.1]+1./[(x-3).^4+0.01];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
返回matlab主界面
输入:
temp=[1,2,3;4,5,6];
f=f31(temp) %验证x是矩阵输入,程序能跑
x=0:0.01:4;
f=f31(x);
plot(x,f)
2题
在Matlab下输入：edit，然后将下面两行百分号之间的内容，复制进去，保存
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function dydx=zh_lankesterljy(x,y)
dydx=x.^2./y-x.*cos(y);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
在Matlab下面输入：
t_end=5;
y0=[1];
[x,y]=ode45('zh_lankesterljy',[0,t_end],y0);
plot(x,y);
xlabel('x');
ylabel('y');
求MATLAB代码
clear;clc
[x,y]=meshgrid(linspace(-5,5));
for k=linspace(-4,4)
mesh(x,y,x.^2+y.^2+k*x.*y);
legend(sprintf('k=%.2f',k),'location','south');
zlim([-100,100]);
pause(0.01)
endk>2或k<-2时为马鞍面；k=±2时为柱面；-2