单项选择题
A.y=(1/2)x+2 B.y=(1/3)x+1 C.y=(1/2)x+3 D.y=(1/4)x+1
A.(0,2) B.(0,-2) C.(0,-1) D.(0,1)
A.e-x+2x(1-e-1) B.e-x+2x(1-e-2) C.e-x+2x(1-e-3) D.e-x+2x(1-e-4)