判断下列各组中的两个函数是同一函数的为()
(1)y1=(x+3)(x−5)x+3,y2=x-5;
(2)y1=
x+1
x−1,y2=
(x+1)(x−1);
(3)y1=x,y2=
x2;
(4)y1=x,y2=3x3
.
A.(1)(2)
B.(2)(3)
C.(4)
D.(3)(4)