Question

find the equation of tangent and normal to the curve xy=16 at (-4),(-4)

Answer 1

GIVEN,
XY=16
DIFFERENTIATE ON BOTH SIDES FOR GETTING TANGENT SLOPE
Y+Xm=0 (where m is slope)
m=-1(since X=-4,Y=-4)
NOW WE GOT TANGENT SLOPE AS -1
FROM Y=mX+C 
-4=4+C
C=-8
SO,TANGENT EQN IS X+Y+8=0
SIMILARLY NORMAL EQN IS X-Y=0(SINCE SLOPE IS 1)