绘制物流地图

Question

我目前正试图在同一个图上绘制f(x) = r*x*(1-x) (其中r =3)和y=x，方法是：

syms r x;
f = symfun(r*x*(1-x), x)
r = 3
plot(f,x)
plot(x,x)

但是我的代码总是导致错误：

Error using plot
A numeric or double convertible argument is expected

请有人帮我指出我哪里出了问题。

Answer 1

错误非常明显:将一个数值参数传递给plot。你是在给它一个象征性的功能。只管用

r = 3;
x = 0:0.1:10; %// set some x
f = (r.*x.*(1-x)); %// dots make the multiplication element-wise
figure; %// opens figure
hold on %// plots multiple things in one figure
plot(f,x)
plot(x,x,'r') %// produces a red plot

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