Unexpected result linspace function

Today I am working with

linspace

function. I used it as

x = linspace(x1,x2,(x2-x1)/deltax+1)

When I passed the value of x1, x2, deltax as:

x1=0.2;
x2=0.5;
deltax=0.1;

I got the result

x = 0.2    0.35    0.5

I try again with

x = linspace(0.2, 0.5, 4)

the result was as expected:

x = 0.2    0.3    0.4    0.5

I do not know it is a bug or other side effect of linspace function. Please help me to understand this. Because if I try:

x1=0.2;
x2=0.6;
deltax=0.1;

The result was good

x = 0.2    0.3    0.4    0.5    0.6

Thank you in advance for your consideration. The following image is the console command I tried:

Answer 1

[Mark Sherstan]

It is due to round off error. Linspace documentation states the following regarding the fuction: If n is not an integer, linspace rounds down and returns floor(n) points. The number is really close to 4 but not 4 so linspace is rounding the number down to 3 or "flooring" it. The other case is exactly 5 and you dont have that issue. Try the following in MATLAB and you will see:

x1=0.2;
x2=0.5;
deltax=0.1;

x = (x2-x1)/deltax+1

x == 4 

>> False

x1=0.2;
x2=0.6;
deltax=0.1;

x = (x2-x1)/deltax+1

x == 5

>> True

[Nguyen Trung Kien]

Thank you so much for your explaination. This helped me to understand and not confuse more.