Exercise 7.5.3

The hypothesis in Theorem 7.5.1 (i) that F ( x ) = f ( x ) for all x [ a , b ] is slightly stronger than it needs to be. Carefully read the proof and state exactly what needs to be assumed with regard to the relationship between f and F for the proof to be valid.

Answers

We use the Mean Value Theorem to ensure that for all subintervals of a particular partition [ x k 1 , x k ] , we have F ( x k ) F ( x k 1 ) = F ( t k ) ( x k x k 1 ) . But the MVT does not require that F is differentiable at the endpoints, so we can relax the requirement slightly and have F ( x ) = f ( x ) over the open interval ( a , b ) .

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2022-01-27 00:00
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