Result discrepancies with "polygonCentroid"

[Mishal0488]

Hi Guys

I have attached my code below.

So I have a situation whereby I am calculating the centroid of the reaction
forces from a beam that's on an elastic foundation.

The first part of the code uses the "polygonCentroid" function which yields
a solution of 0.49787 (only considering the x component)

When implementing the mechanics equations to calculate the centroid, I
attain a solution of 0.49362.
I have attached the equation also.

Both these solutions differ slightly, although I would like some insight as
to why? I assume that there may be some limitations on the "polygonCentroid"
function causing this issue.



>> R(1) = translation(1)*ss1
R = -21345.31066
>> R(2) = translation(2)*ss1
R =

  -21345.31066  -20807.18804

>> points = [0 0;0 R(1);l1 R(2);l1 0;0 0]
points =

       0.00000       0.00000
       0.00000  -21345.31066
       1.00000  -20807.18804
       1.00000       0.00000
       0.00000       0.00000

>> polygonCentroid(points)
ans =

       0.49787  -10538.69715

>>     x = [0 l1];
>>     coefficients = polyfit([x(1) x(2)],[R(1) R(2)],1);
>>     R_l1_static = trapz(x,R)
R_l1_static = -21076.24935
>>     R = [coefficients(1)*x(1)^2+coefficients(2)*x(1)
>> coefficients(1)*x(2)^2+coefficients(2)*x(2)];
>>     top = trapz(x,R);




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