How can this probability function be entered?

I'm very new to matlab. I want to take this equation and use matlab to graph it:

I used this code

The variable P is created but it has a value for the first element, then all zeros.

Answer 1

[Star Strider]

You have to vectorise your assignment for ‘P’:

k = 1.3806488E-23;
e = 6.0217657E-19;
z = 2;
Vh = 1E-3;
T1 = 25+273.15;
T2 = 37+273.15;
V = linspace(-0.1, 0.09);
VV = V-Vh;
P = 1./(1+exp(-z*e*(VV/(k*T1))));

figure(1)
plot(V, P)
grid

See Matrix vs Array Operations for details.

[Matthew Nanos]

Thank you

[Star Strider]

My pleasure!

Answer 2

[Greig]

Change P to

P = (1./(1+exp(-z*e*(VV/(k*T1)))));

Since the (1+exp(..)) is a vector you have to use array division (./)