[解題] 高一數學多項式
1.年級:高中一年級
2.科目:數學
3.章節:多項式
4.題目:解2x^3-8x^2-5x-7=0
5.想法:
(1)這是三次多項式,根據有理係數方程式虛根與無理根必成雙的道理,
則另一根必為有理根!!!(<--這想法是正確的嗎??)
(2)但依據牛頓定理,x有可能等於1,-1,7,-7,1/2,-1/2,7/2,-7/2
x=1, 2-8-5-7不等於0
x=-1, -2-8+5-7不等於0
x=7, 686-392-35-7不等於0
x=-7, -686-392+35-7不等於0
x=1/2, 0.25-2-2.5-7不等於0
x=-1/2, -0.25-2+2.5-7不等於0
x=7/2, 85.75-98-17.5-7不等於0
x=-7/2, -85.75-98+17.5-7不等於0
帶進去皆不符合@@
(3)想請問各位,究竟要如何才能解此方程式呢??
謝謝解答
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