4.
已知\(x+y+z=1\)、\(x^2+y^2+z^2=2\)、\(x^3+y^3+z^3=3\)，則\(x^4+y^4+z^4\)的值為何？
(A)\(\displaystyle \frac{25}{6}\) (B)\(\displaystyle \frac{25}{7}\) (C)\(\displaystyle \frac{25}{8}\) (D)\(\displaystyle \frac{25}{9}\)
https://math.pro/db/thread-799-1-1.html
5.
已知\(a,b,c\)為正數，且\(a+b+c=1\)，則\(\displaystyle (\frac{1}{a}-1)(\frac{1}{b}-1)(\frac{1}{c}-1)\)的最小值為何？
(A)10 (B)9 (C)8 (D)7
(100成淵高中，連結有解答
https://math.pro/db/viewthread.php?tid=1128&page=1#pid3466
我的教甄準備之路 \(a+b=1\)求極值，
https://math.pro/db/viewthread.php?tid=661&page=1#pid1079)
