# Integral Question

## Homework Statement

Can someone explain to me the logic of this statement:

"Since the value of f (x, y) is unchanged when we swap x with y,

$$\int_0^1 \int_0^x f (x+y)dydx = 1/2 \int_0^1 \int_0^1 f (x+y)dydx.$$"

## The Attempt at a Solution

$$\int_0^1 \int_0^x f (x+y)dydx = \int_0^1 \int_0^y f (y+x)dxdy$$

But I do not think that is the same.