Ex 82

The temperature at a point \((x, y)\) on a flat metal plate is given by
\[T(x, y) = \frac{60}{1 + x^2 + y^2}\]
where \(T\) is measured in °C and \(x, y\) in meters.

Find the rate of change of temperature with respect to distance at the point \((2, 1)\) in
(a) the \(x\)-direction
(b) the \(y\)-direction.