Hi,
During some calculations I came across a simple but strange integration problem. Two terms of this complicated equation can be given in simplified form as follows -
(1) I1 = Integrate[y, {x, X1, X2}]
(2) I2 = Integrate[1, {x, X1, X2}, {y, Y1, Y2}]
.Where y is not a function of x but at two extreme values of x (X1 and X2) it has different values (say Y1 and Y2). Now my problems are
1) whether consider y as a constant in this integration or not ? If I do (which seems reasonable), then my final result of I1 would be y(X2-X1), but y is not a real parameter and I assumed it for the sake of calculation and I need the solution of I1 & I2 in terms of X1, X2, Y1 and Y2.
2) If I consider y also as a variable and apply the limits (Y1 & Y2), my solution for I1 would be (Y2-Y1)(X2-X1). Would it be correct to do so as I1 is integral over x only ??
3) Also if I apply the limits for both x and y, then solutions to both I1 and I2 would be (Y2-Y1)(X2-X1). Is it justified to have same solution for I1 and I2.

I will really appreciate any suggestion on this weird problem. Thanks. SG