z
= 1 +
x
² +
y
²
u
= ⟨1/√2, 1/√2⟩ at
P
₀(1, 1)
secant slope = 3.528
(
f
(P) −
f
(P₀) ) /
s
= 2√2 +
s
secant
3.528
→
tangent
2.828
Watch:
▶
s
→ 0
▶ Play
Spin
step
s
=
0.70