The bounds of an integral

1. Apr 9, 2013

wahaj

When taking a definite integral that is bound by two points a and x where a is a constant and x is a variable, which quantity do I consider the upper limit of the integral and which quantity is the lower limit?
$$\int^a_x x$$
this integral is written as
$$-\int^x_a x$$ in my book.
When I use integrals in my dynamics class I can easily tell which limit goes where but this is much tougher in math class because all I am given are random functions to integrate.

2. Apr 9, 2013

HallsofIvy

You have to be told to integrate "from a to b".

3. Apr 9, 2013

wahaj

ok. I always assumed it didn't really matter, I can't believe I got so many questions right doing what I did.