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4<br />
±1, ±2, ±4 ±1, ±2 4 <br />
x − 4 <br />
<br />
4x 3 −12x 2 −15x −4 x − 4<br />
−4x 3 +16x 2 4x 2 + 4x + 1<br />
4x 2 −15x<br />
−4x 2 +16x<br />
x −4<br />
−x 4<br />
0<br />
4x 3 − 12x 2 − 15x − 4 = (x − 4)(4x 2 + 4x + 1) = (x − 4)(2x + 1) 2 ,<br />
x = 4 x = −1/2 P1 = (−1/2, 0) P2 = (4, 0)<br />
f<br />
∂xf(x, y) = 12(x 2 + y 2 − x) 2 (2x − 1) − 108x(x 2 + y 2 )<br />
= 12((x 2 + y 2 − x) 2 (2x − 1) + 9x(x 2 + y 2 ))<br />
∂yf(x, y) = 12y(2(x 2 + y 2 − x) 2 − 9(x 2 + y 2 )).<br />
P2 P3 P4 <br />
df(4, 0) = 12(144 · 7 − 36 · 4) dx = 144 · 72 dx (4, 0) <br />
x = 0 x = 4<br />
df(0, 3 √ 3/2) = 729<br />
16 (− dx + √ 3 dy) (0, 3 √ 3/2) <br />
−x + √ 3y = q q = 9/2 −x +<br />
√ 3y = 9/2.<br />
(0, −3 √ 3/2) x + √ 3y = −9/2<br />
P3 P4 ∂yf(P3) = 0 ∂yf(P4) = 0 <br />
∂yf(P1) = ∂yf(P2) = 0 <br />
<br />
ρ ≥ 0 − 3√ 4 ≤ 3√ 4ρ − 3 3√ ρ ≤ 3√ 4 <br />
z(ρ) = 3√ 4ρ − 3 3√ ρ z(0) = 0 <br />
˙z(ρ) = 3√ 4 − ρ −2/3 > 0<br />
z(ρ) ρ = 1/2 ¨z(ρ) > 0 <br />
z(1/2) = − 3√ 4 ρ > 1/2 <br />
3√ 4 ρ ρmax <br />
z(ρmax) = 3√ 4 θ = 0 (4, 0) <br />
ρ 1/2 <br />
ρ 4 ρ 2 16 f Γ <br />
ρ Γ <br />
H(ρ, θ) := z(ρ) − 3√ 4 cos θ = 0 ρ <br />
θ ˙z(ρ) = 0 <br />
ρ = 1/2 ρ = ρ(θ) C 1 <br />
dρ<br />
dθ (θ) = −∂θH(ρ(θ), θ)<br />
∂ρH(ρ(θ), θ) = − 3√ sin θ<br />
4<br />
˙z(ρ(θ) ,<br />
θ = 0, π Γ <br />
ρ = 1/2<br />
(4, 0) (0, 0) (−1/2, 0) (0, 0) ρ <br />
(4, 0) ρ