Solution
= Solution
At fixed $t$, <streamlines> satisfy $(\alpha+t)y^2/2-x=C$: right-opening parabolas, more tightly curved at $t=1$ than at $t=0$.
= Solution
At fixed $t$, <streamlines> satisfy $(\alpha+t)y^2/2-x=C$: right-opening parabolas, more tightly curved at $t=1$ than at $t=0$.