$\"\"$

The standard form for a parabola that opens vertically is $\"\"$ .

If the vertex is at the origin $\"\"$ .

Substitute $\"\"$ in $\"\"$ .

The equation of parabola is $\"\"$ .

If the vertex of the umbrella is at the origin, then the two tips of the umbrella occur at the points $\"\"$ and $\"\"$ .

Substitute one of these points into the equation and solve for $\"\"$ .

Substitute $\"\"$ in $\"\"$ .

$\"\"$

$\"\"$ .

Substitute $\"\"$ in $\"\"$ .

$\"\"$

$\"\"$ .

The parabola equation is $\"\"$ .

$\"\"$

The parabola equation is $\"\"$ .