As shown in the figure, there is a fountain in the center of the circular flower bed pool, and the water pipe OP =1m. After the water is ejected from the nozzle P, it is parabolic, first rising to the

As shown in the figure, there is a fountain in the center of the circular flower bed pool, and the water pipe OP =1m. After the water is ejected from the nozzle P, it is parabolic, first rising to the highest point and then falling. If it is the highest, Solution: As shown in the figure, the plane rectangular coordinate system is established, and the parabolic equation is x2 =-2py (P > 0).

Then P(- 1,-1) is substituted into the parabolic equation to obtain p= 12, and the parabola x2=-y is substituted into the point (x, -2).

X=2, that is, the minimum radius of the pool is r=( 1+2)m,

The minimum diameter of swimming pool is 2r = (2+22) meters.

So the answer is: 2+22.