Math man werk with x^2 after him thank yuno all bout x... x=strate line, x^2...kervs, mostlee parabolas... If yu loop rope over top av 2 poles & let it dangel in tween, rope make parabola..... Trajektory av rok or sheel yu shoot/thro...if ignore aer resist... & konsider flat-erth approx, then path it take=parabola Kloeser...ellips & that yuze x^2 & y^2