作业帮检查一下哪里错了 MATLABsyms x y=log(x)/x;d1=diff(y);d2=diff(d1);x=0:0.2:20;axis([0,20,-9 1]);plot(x,y),grid onhold onx1=fzero(d1,[0,20]);plot(x1,y1,'*')text(x1,y1,'极大值点')hold onx2=fzero(d2,[0,20]);plot(x2,y2,'r*')text(x2,y2,'拐点')
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 15:12:40
![检查一下哪里错了 MATLABsyms x y=log(x)/x;d1=diff(y);d2=diff(d1);x=0:0.2:20;axis([0,20,-9 1]);plot(x,y),grid onhold onx1=fzero(d1,[0,20]);plot(x1,y1,'*')text(x1,y1,'极大值点')hold onx2=fzero(d2,[0,20]);plot(x2,y2,'r*')text(x2,y2,'拐点')](/uploads/image/z/3164713-25-3.jpg?t=%E6%A3%80%E6%9F%A5%E4%B8%80%E4%B8%8B%E5%93%AA%E9%87%8C%E9%94%99%E4%BA%86+MATLABsyms+x+y%3Dlog%28x%29%2Fx%3Bd1%3Ddiff%28y%29%3Bd2%3Ddiff%28d1%29%3Bx%3D0%3A0.2%3A20%3Baxis%28%5B0%2C20%2C-9+1%5D%29%3Bplot%28x%2Cy%29%2Cgrid+onhold+onx1%3Dfzero%28d1%2C%5B0%2C20%5D%29%3Bplot%28x1%2Cy1%2C%27%2A%27%29text%28x1%2Cy1%2C%27%E6%9E%81%E5%A4%A7%E5%80%BC%E7%82%B9%27%29hold+onx2%3Dfzero%28d2%2C%5B0%2C20%5D%29%3Bplot%28x2%2Cy2%2C%27r%2A%27%29text%28x2%2Cy2%2C%27%E6%8B%90%E7%82%B9%27%29)
检查一下哪里错了 MATLABsyms x y=log(x)/x;d1=diff(y);d2=diff(d1);x=0:0.2:20;axis([0,20,-9 1]);plot(x,y),grid onhold onx1=fzero(d1,[0,20]);plot(x1,y1,'*')text(x1,y1,'极大值点')hold onx2=fzero(d2,[0,20]);plot(x2,y2,'r*')text(x2,y2,'拐点')
检查一下哪里错了 MATLAB
syms x
y=log(x)/x;
d1=diff(y);d2=diff(d1);
x=0:0.2:20;axis([0,20,-9 1]);
plot(x,y),grid on
hold on
x1=fzero(d1,[0,20]);
plot(x1,y1,'*')
text(x1,y1,'极大值点')
hold on
x2=fzero(d2,[0,20]);
plot(x2,y2,'r*')
text(x2,y2,'拐点')
检查一下哪里错了 MATLABsyms x y=log(x)/x;d1=diff(y);d2=diff(d1);x=0:0.2:20;axis([0,20,-9 1]);plot(x,y),grid onhold onx1=fzero(d1,[0,20]);plot(x1,y1,'*')text(x1,y1,'极大值点')hold onx2=fzero(d2,[0,20]);plot(x2,y2,'r*')text(x2,y2,'拐点')
我给你写一个算了
close all
clear,clc
syms x
f=@(x)log(x)./x;
eval(['f1=@(x)' char(diff(f(x))),';','f2=@(x)' char(diff(f(x),2)),';']);
span=[0.1,20];
x1=fzero(f1,span);x2=fzero(f2,span);
x=0:.1:20;
y=f(x);
y1=f(x1);y2=f(x2);
plot(x,y,x1,y2,'ro',x2,y2,'go','linewidth',2,'markersize',7)
h=legend('$\ y=\frac{\ln(x)}{x}$','$\frac{d}{dx}(\frac{\ln(x)}{x})=0$','$\frac{d^2}{dx^2}(\frac{\ln(x)}{x})=0$','Location','Best');
set(h,'interpreter','latex','fontsize',14)
grid on;axis([0,20,-3 1]);