Question

函数y=2ln(x2+1)的导数是（　　）

A． 2ln2×x x2+1 2ln(x2+1)	B． 2log2e×x x2+1 2ln(x2+1)
C． ln2 x2+1 2ln(x2+1)	D． 2ln2 x2+1 2ln(x2+1)

Answer 1

由复合函数的求导法则可得，y′=2ln(1+x2)•[ln（x²+1）]′ln2
=2ln(1+x2)•

1

1+x2

•（1+x²）′ln2
=2ln(x2+1)•

2x

1+x2

•ln2
故选A