下列函数f(x)与9(x)相等的是()
f ( x ) = x 2 , g ( x ) = Vx 4
B . f ( x ) = X , g ( x = ( vx ) 2
- Vx - 1 , g ( x ) = f ( x ) - VX + 1 8 ( x ) = V 3
D . f ( x ) - , g ( x ) = x + 1