$(3)$ A particle on the $\backslash ($ x $\backslash )-$axis is moving to the right at $2$ units per second. A second particle is moving down the $\backslash ($ y $\backslash )-$axis at the rate of $3$ units per second. At a certain instant the first particle is at the point $\backslash ((5,0)\backslash ),$ and the second is a the point $\backslash ((0,7)\backslash ).$ How rapidly it the angle between the $\backslash ($ x $\backslash )-$axis and the line joining the two particles changing at that instant? Are the particles moving towards or away from ench other at that instant?