I will put
on the limits to show what variable the
limits are on, namely x, since we will be changing the limits:
Let
Then
or
and
So we substitute
for
and
for
And we can take out the negative sign in front of the integral:
But the limits are on x. We want to change the limits
so that they will be on u rather than x.
To do that we substitute the limits for x in the equation
for u which is
when
,
and
when
,
,
so we change the limits to:
and we use the power formula
Edwin