Question

函数f(x)=log2(x+(1/x-2) ) (x>2)的值域为?..

Answer 1

x>2

x + 1/(x-2) = (x-2)+2+1/(x-2) = 2 + [√(x-2)-1/(√(x-2)]^2 + 2 ≥ 4

f(x)=log2(x+(1/x-2) ) ≥ log 2 (4) = 2

值域：【2,+∞）