Question

解关于X的不等式1-(10^x-1)/(10^x+1)>1/(100^x-1)

Answer 1

设t=10^x>0

1-(t-1)/(t+1)>1/(t^2-1)

2/(t+1)>1/(t+1)(t-1) [t+1>0]

2>1/(t-1)

所以t3/2

10^x3/2

所以xlg3/2

解集是(-无穷大,0)并(lg3/2,+无穷大)