求函数f(x)=x2ln(1+x)在x=0处的n阶导数f(n)(0)(n≥3)

求函数f(x)=x2ln(1+x)在x=0处的n阶导数f(n)(0)(n≥3).
2025-04-14 01:02:49
推荐回答(1个)
回答(1):

[ln(1+x)](k)

(?1)k?1(k?1)!
(1+x)k+1
,(k=0,1,2,…)
(uv)(n)u(0)v(n)+
C
u(1)v(n?1)+
C
u(2)v(n?2)+…+
C
u(n)v(0)

f(n)(x)=x2?
(?1)n?1(n?1)!
(1+x)n
+2nx?
(?1)n?2(n?2)!
(1+x)n?1
+n(n?1)?
(?1)n?3(n?3)!
(1+x)n?2

f(n)(0)=n(n?1)?
(?1)n?3(n?3)!
(1+0)n?2
=n(n?1)?(?1)n?3(n?3)!=
(?1)n?3n!
n?2