应该是(1-x)/(1+x)吧 不然也太简单了
f(x)=log2[(1-x)/(1+x)]
=log2[2/(x+1)-1]
2/(x+1)值域是 (-无穷,0)U(0,+无穷)
2/(x+1)-1值域是 (-无穷,-1)U(-1,+无穷)
log2[2/(x+1)-1]值域是 (-无穷,+无穷)
所以值域是 (-无穷,+无穷)
应该是(1-x)/(1+x)吧 不然也太简单了
f(x)=log2[(1-x)/(1+x)]
=log2[2/(x+1)-1]
2/(x+1)值域是 (-无穷,0)U(0,+无穷)
2/(x+1)-1值域是 (-无穷,-1)U(-1,+无穷)
log2[2/(x+1)-1]值域是 (-无穷,+无穷)
所以值域是 (-无穷,+无穷)