A Red Kite $(a$ type $of$ bird$)is$ flying above Oxford $in$ a vertical circular pattern

described $byx=cost,z=sint,$ above a heat source. The temperature distribution $of$

the air $in$ this plane $is$ given $by$

$T=20$exp$(-x^2)-(z+1{)}^3$

Find, $in$ two different ways, the rate $of$ change $of$ temperature that the bird experiences

$as$ a function $oft.$