Bourbaki

Corollary

Tag 0852, permanent. Cite it as [Bourbaki, Tag 0852].

Functions of a Real Variable, chapter I, § 3. DERIVATIVES OF HIGHER ORDER

If ff is a finite real function with a derivative of order n+1n + 1 on I, and if m≤f(n+1)(x)≤Mm \leq f^{(n+1)}(x) \leq M on I, then for all x≥ax \geq a in I one has

m(x−a)n+1(n+1)!≤rn(x)≤M(x−a)n+1(n+1)! m \frac{(x - a)^{n+1}}{(n + 1)!} \leq r_n(x) \leq M \frac{(x - a)^{n+1}}{(n + 1)!}
and the second term cannot be equal to the first (resp. to the third) unless f(n+1)f^{(n+1)} is constant and equal to mm (resp. MM) on the interval [a,x][a, x].

The proof proceeds in the same way, but applying th. 1 of I, p. 14.

Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

Transcribed from the printed volume. Not translated.