第一问y=t-1代入(y-1)^2-(y-1)-1=xx=y^2-2y+1-y=y^2-3y+1第二问同样直接代入y^(1/2)=a^(1/2)-a^(1/2)·(cosφ)^2=a^(1/2)(sinφ)^2y=a(sinφ)^4
