I am finding it difficult to write extended langmuir isotherm using summation.

I am new to MATLAB so the equation looks like this.

Gsel = sum(Gsli(1:4))*((yi*P)/Pli)/(1+sum(yj*P/Plj(1:4))

Answer 1

[Walter Roberson]

The meaning of that is not clear. The expression contains both p and using exactly the same symbol p . That tells us that the non-subscripted places refer to an entire 2D array and the refer to a specific entry in that array. could be understood as dividing the entire 2D matrix by a particular value, and it might not be unreasonable to sum a bunch of those, getting a 2D array. But such 2D arrays appear in both the numerator and denominator, and it is not at all clear what division of two 2D arrays is intended to mean in this context.

Also the information we are given is not enough to know that no entry is 0.