Matlab不绘制函数间隔

Question

I want to plot the following mathemathical function:

I tried using the following code:

x= -3:0.1:3;
x1 = x(x>2 & x<2);
x2 = x(x==2)
y1 = (x1)+1
y2 = 2
plot([x1 x2], [y1 y2])

Why is it giving me an empty window?

Answer 1

It is not possible for the following conditional to ever be true since any number can't be simultaneously greater than and less than 2

x > 2 & x < 2

As a result, x1 is an empty vector and x2 is just going to be 2 , so your plotting command will just yield a single point at (2,2).

You want to use a logical or ( | ) instead

x1 = x(x > 2 | x < 2);

Also a better way to plot this would be the following

y = x + 1;          % Set all values to x + 1
y(x == 2) = 2;      % Replace those that meet your criteria

plot(x, y)

As a side note, it's generally a bad idea to use == to compare floating point numbers. You should instead use eps to check if two floating point numbers are equal:

y(abs(x - 2) < eps) = 2;