Bourbaki

Exercise 4, § 2

Functions of a Real Variable, III, 125

For every real xx and every number p>1p > 1 prove the inequality

∣1+x∣p≤1+px+p(p−1)2x2+⋯+p(p−1)…(p−m+2)(m−1)!xm−1+p(p−1)…(p−m+1)m!∣x∣m+hp ∣x∣p |1 + x|^p \leq 1 + px + \frac{p(p-1)}{2} x^2 + \cdots + \frac{p(p-1)\ldots(p-m+2)}{(m-1)!} x^{m-1} \\ + \frac{p(p-1)\ldots(p-m+1)}{m!} |x|^m + h_p\ |x|^p
where one puts m=[p]m = [p] (the integer part of pp) and
hp=p(p−1)…(p−m+1)(m−1)!∫01zp−m(1−z)m−1 dz. h_p = \frac{p(p-1)\ldots(p-m+1)}{(m-1)!} \int_0^1 z^{p-m}(1-z)^{m-1}\ dz.

Solution

No solution has been written yet.

Transcribed from the printed volume. Not translated.