# Thread: polar/cartesian intergration + excel

1. ## polar/cartesian intergration + excel

i have a problem with cartesian vs polar intergration for area over an angle.

equation as follows:

x=E cos 3a + R cos a
y=E sin 3a + Rsin a

I have integrated in both forms however the area are not the same

i have also plotted the function in excel and am not able to get the same points (simplified function)

can anybody explain why is this so