The temperature at a point (x,y) on a flat metal plate is given by T(x,y)=19/(2+x^2+y^2), where T is measured in Celsuis and x,y in meters. Find the rate of change of temperature with respect to distance at the point (1,2) in the following directions.
Athe x-direction
Bthe y-direction
Athe x-direction
Bthe y-direction