University Maths Notes: Calculus – Differentiating Under the Integral Sign
Suppose we have a function of two variables
and
we need to differentiate
with
respect to![]()
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This is called differentiating under the integral. Notice the
above formula has the limits as functions of
We
are integrating with respect to
but
the limits are not values of
They
are functions of
which
imply values of
If
the limits are pure numbers the first two terms become zero and we
recover the relationship![]()
Example: Differentiate
with
respect to![]()
![]()
![]()
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Example: Differentiate
with
respect to![]()
![]()
![]()