------------
Welcome to March Calculus Madness!
------------
For the two-variable function f(x,y), can we assume that ∫ ∫ f(x,y) dx dy = ∫∫ f(x,y) dy dx?
Two simple examples:
Equation 1:
∫ ∫ x^2 + y^2 dx dy
= ∫ x^3/3 + y^2 ∙ x + C1 dy
x^3 ∙ y/3 + y^3 ∙ x/3 + C1 ∙ y + C2
Equation 2:
∫ ∫ x^2 + y^2 dy dx
∫ x^2 ∙ y + y^3/3 + C1 dx
x^3 ∙ y/3 + y^3 ∙ x/3 + C1∙ x + C2
However, for both Equation 1 and Equation 2 to be equal:
x^3 ∙ y/3 + y^3 ∙ x/3 + C1 ∙ y + C2 = x^3 ∙ y/3 + y^3 ∙ x/3 + C1∙ x + C2
C1 ∙ y = C1 ∙ x
y = x
By this example alone, we cannot assume that ∫ ∫ f(x,y) dx dy = ∫∫ f(x,y) dy dx.
Eddie
All original content copyright, © 2011-2022. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.