Answer:
Tangent at (1,2) has value
. And (-2, 4) is the point of intersection of horizontal tangent.
Step-by-step explanation:
Given curve equation,

To find tangent at (x,y)=(1,2) and point of intersection of horizontal tangent, differentiate (1) withrespect to x we get,


At (1, 2), tangent line is,
To find point of intersection of horizontal tangent we have to do,

Thus,
At x=0, y=0
but snce,

at (0,0) there exist a vertical tangent. And,
At x=-2, y=4.
Thus (-2, 4) is the point of intersection of horizontal tangent.