热心网友

y=2/3*√(9-x^2) (-3=y^2=4/9*(9-x^2) (y=0)---x^2=9/4*(4-y^2) x=x=-3/2*√(4-y^2) (-3=

热心网友

y=-3根号下1-四分之x方 (-2<=x<=2)