To obtain the tangent plane from first principles, compute N, a normal at P::
then implement the vector form of the equation of a plane:
|
|
|
|
|
|
|
|
|
|
|
|
which, when rearranged, can be written as .
Approximating by its first-degree Taylor polynomial
means
|
|
|
|
|
|
|
|
Finally, from , obtain , or
|
|
|
|
|
|
|
|
|
|
since , and .