integration without using integration

[isabella]

i'm having a problem with this integration formula..
f=(double integration cos a cos b)/(pi*d^2)dA

i have to insert this formula into an excel sheet but in excel to do integration i need to use an alternative way as the vba codes does not provide any formula for integration.

[Icebreaker]

What's the area of integration bounded by?

[isabella]

the boundary can be set on our own.

[isabella]

i mean it depends on the area that i chose (dA).i was told that this involves a summation of the values of F.the whole area is divided into many small areas(dA).

[steven187]

hello isabella

well to me a great way to do integration with out using integration is most likely through a monte carlo approach, since we are dealing with double integrals we are trying to find the volume of a 3D shape, the Area you are talking about sounds like the base of this 3D shape now if you generated randomly distributed points over this area, and found the average of the function values at all these points and multiply it by the area of the base you will indeed find the solution to the double integral which is the volume of the 3 dimentional shape, but see this will all be based upon approximations and the more points you use the more accurate you anwser will be

steven