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x^4+x^3+1的因式分解

因式分解:x^4+x^3+1 一个学生问的题目,好几个老师一起想,都没有一个好方法来分解,哪位高手帮忙一下!

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2008-06-12

75 0
1. 显然 x^3-4x-1=0 有个根,22的实系数多项式都可以在实数范围内分解.

2008-06-12

44 0
x^4+x³+1在实数范围内无法分解

2008-06-12

72 0
    设 f(x)=x^4+x³+1 --->f'(x)=4x³+3x²=x²(4x+3) --->f(x)有极小值f(-4/3)>0 --->f(x)=0无实根,不能分解出一次式 设 f(x) = x^4+x³+1 = (x²+ax+1)(x²+bx+1)           = x^4+(a+b)x³+(ab+2)x²+(a+b)x+1 比较三次项系数--->a+b=1 比较一次项系数--->a+b=0,矛盾,f(x)也不能分解出二次式 所以,f(x)=x^4+x³+1在实数范围内无法分解。
    。

2008-06-12

70 0
    好像没法分解。
     >> factor(x^4+x^3+1) ans = x^4+x^3+1 >> solve('x^4+x^3+1','x') ans = -1/4+1/12*3^(1/2)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+1/12*(-(-18*(108+12*i*687^(1/2))^(1/3)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+6*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)*(108+12*i*687^(1/2))^(2/3)+288*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+18*3^(1/2)*(108+12*i*687^(1/2))^(1/3))/(108+12*i*687^(1/2))^(1/3)/((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2))^(1/2) -1/4+1/12*3^(1/2)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)-1/12*(-(-18*(108+12*i*687^(1/2))^(1/3)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+6*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)*(108+12*i*687^(1/2))^(2/3)+288*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+18*3^(1/2)*(108+12*i*687^(1/2))^(1/3))/(108+12*i*687^(1/2))^(1/3)/((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2))^(1/2) -1/4-1/12*3^(1/2)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+1/12*6^(1/2)*((3*(108+12*i*687^(1/2))^(1/3)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)-((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)*(108+12*i*687^(1/2))^(2/3)-48*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+3*3^(1/2)*(108+12*i*687^(1/2))^(1/3))/(108+12*i*687^(1/2))^(1/3)/((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2))^(1/2) -1/4-1/12*3^(1/2)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)-1/12*6^(1/2)*((3*(108+12*i*687^(1/2))^(1/3)*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)-((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)*(108+12*i*687^(1/2))^(2/3)-48*((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2)+3*3^(1/2)*(108+12*i*687^(1/2))^(1/3))/(108+12*i*687^(1/2))^(1/3)/((3*(108+12*i*687^(1/2))^(1/3)+2*(108+12*i*687^(1/2))^(2/3)+96)/(108+12*i*687^(1/2))^(1/3))^(1/2))^(1/2) 。

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