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dbb04
Oct27-04, 05:46 AM
I have this equation



\int_t^T n(s) (1- e^{-c (T-s)}) ds = c F(T)



and I need to differentiate both sides with respect to T


\frac{\partial }{\partial T}


to get the following result


\int_t^T n(s) ( e^{-c (T-s)}) ds = \frac{\partial F(T)}{\partial T}


How was it done ? What integration and differentiation rule was used ? If you could show it step by step I would appreciate.

shmoe
Oct27-04, 07:58 AM
I would rewrite the integral:


\int_t^T n(s) (1- e^{-c (T-s)}) ds = \int_t^T n(s)ds-e^{-cT}\int_t^T n(s) e^{cs}} ds


Then use the tried and true fundamental theorem of calculus (assuming g is continuous):

\frac{d}{dT}\int_{a}^{T}g(s)ds=g(T)

The purpose of rewriting was to remove any potentially confusing dependance of T from the integrands.

dbb04
Oct27-04, 09:03 AM
Yeah, sure. Now I see it.

Thanks very much for the prompt reply