curva  a punta di proiettile, cartesiana

k^2 * y^2  - h^2*x^2= x^2  *  y^2

k = 1 (slider from 0.5 to 2, step 0.1)
h = 1 (slider from 1 to 5, step 0.1)
a: k^(2) * y^(2) - h * 2 * x^(2) = x^(2) * y^(2)