a=1b=1

fx=1nxx+1+1x

f（x）-（xx-1+kx+kx）=

11-x2（21nx+k-1（x2-1x

k-ooo]

1nxx+1+1x&62;xx--1x

k-1&6o;2x1nx1-x2

k-ooo]

gx=2x1nx1-x2gx）=（21nx+2）（1-x2+4x21nx（1-x2）2

k-ooo]

4

5

8

91o

+1

+2

+3