第1744题：水中月
能产生上类似水中月倒影图形的函数是( )
A. x2+y2=(12)y+cosy2x^2+y^2=(\dfrac{1}{2})^y + \cos{y^2}x2+y2=(21)y+cosy2
B. x2+y2=(12)y+siny2x^2+y^2=(\dfrac{1}{2})^y + \sin{y^2}x2+y2=(21)y+siny2
C. x2+y2=(12)y+tany2x^2+y^2=(\dfrac{1}{2})^y + \tan{y^2}x2+y2=(21)y+tany2
D. x2+y2=(12)y+coty2x^2+y^2=(\dfrac{1}{2})^y + \cot{y^2}x2+y2=(21)y+coty2
