Plotting (1-2*x)*log((1-x)/x)

Hello!. I am very new to matlab and wanna know how can I plot

y=(1-2*x)*log((1-x)/x) function?

I tried to write it like that but it did not work as i expected.. It plots something else..

thanks..

and also why i cannot plot (1/x)? thanks.

[Geoff Hayes]

Kemal - what is the code that you are using to plot your above y? What have you initialized x as?

[kemal sen]

I used this

x=0:0.2:1;
y=(1-2*x)*log((1-x)/x) ;
plot(x,y)

Answer 1

[Giorgos Papakonstantinou]

The problem occurs inside the log parenthesis. The syntax that you have used tells Matlab to solve the equation:

 x = B/A

for x. Check the documentation for mrdivide to get more a thorough explanation.

If you want to do element-wise arithmetic operations (division, power, etc.) then you have to use . before each operation. Look for more information here.

In your case you have to modify your equation:

y=(1-2.*x).*log((1-x)./x)

Here the log function computes the natural logarithm.

or

 y=(1-2.*x).*log10((1-x)./x)

Here the log10 function computes the logarithm when the base is 10

For example if:

x=0:0.02:1;
y=(1-2*x).*log((1-x)./x) ;

plot(x,y)

the result is:

[kemal sen]

Thank you very much..

Answer 2

[D tk]

plot y=0.5*ln(pi*e),e is exp^1

[Walter Roberson]

plot(0.5*log(pi*exp(1)), 'r*')