A particle is moving with a velocity $\vec { v } = K y \hat { i } + x \hat { j }$, where $K$ is a constant.\\
The general equation for its path is:\\
(1) $y ^ { 2 } = x +$ constant\\
(2) $x y =$ constant\\
(3) $y = x ^ { 2 } +$ constant\\
(4) $y ^ { 2 } = x ^ { 2 } +$ constant