高数数学题3
2个回答

设√(1+4X)为T

Y=(1-T)/(1+T)

Y(1+T)=1-T

Y+YT=1-T

YT+T=1-Y

(Y+1)T=1-Y

T=(1-Y)/(1+Y)

还原:√(1+4X)=(1-Y)/(1+Y)

1+4X=(1-Y)²/(1+Y)²

4X=(1-Y)²/(1+Y)²-1

X=1/4×(1-Y)²/(1+Y)²-1/4

因此反函数为:Y=1/4×(1-X)²/(1+X)²-1/4选择A