前>>536
>>534訂正。
f'(x)=448x^13+480x^9+120x^5+4x
-(384x^11+256x^7+32x^3)√(x^4+1)
-｛(32x^12+32x^8+8x^4)4x^3｝/｛2√(x^4+1)｝
=0
(112x^12+120x^8+30x^4+1)√(x^4+1)
=96x^14+64x^10+8x^6
+96x^10+64x^6+8x^2
+16x^14+16x^10+4x^6
(112x^12+120x^8+30x^4+1)^2(x^4+1)
=96x^14+176x^10+76x^6+8x^2

12544x^24+14400x^16+900x^8+1
+13440x^20+6720x^16+224x^12
+7200x^12+240x^8+60x^4
+12544x^28+14400x^20+900x^12+x^4
+13440x^24+6720x^20+224x^16
+7200x^16+240x^12+60x^8
-96x^14-176x^10-76x^6-8x^2
=0
12544x^28+25984x^24+34560x^20+28544x^16
-96x^14+8564x^12-176x^10+1200x^8-76x^6+61x^4-8x^2+1
=0
x^2=Xとおくと、
12544X^14+25984X^12+34560X^10+28544X^8
-96X^7+8564X^6-176X^5+1200X^4-76X^3+61X^2-8X+1
=0