Expression 8: "y" equals "x" times tangent left parenthesis, "Q" , right parenthesis minus StartFraction, left parenthesis, 9.8 1 , right parenthesis times "x" squared Over left parenthesis, 2 times "v" squared times cos squared left parenthesis, "Q" , right parenthesis , right parenthesis , EndFraction left brace, "x" greater than or equal to 0 , right bracey=x·tanQ−9.81·x22·v2·cos2Qx≥0