x^4-5x^2+10x+24=0

2个回答

  • x^4-5x^2+4 + 10x+20 = 0

    (x^2-1)(x^2-4)+10(x+2)=0

    (x+2)(x^3-x-2x^2+2+10)=0

    (x+2)(x^3-2x^2-x+12)=0

    所以有一个解x=-2

    x^3-2x^2-x+12不能再分解了,可以用三次方程求根公式得到精确解

    他的解分别为

    x1=1/3 (2 - 7/(145 - 3 Sqrt[2298])^(1/3) - (145 - 3 Sqrt[2298])^(1/3)) = -1.88968

    x2=2/3 + (7 (1 + I Sqrt[3]))/(6 (145 - 3 Sqrt[2298])^(1/3)) +

    1/6 (1 - I Sqrt[3]) (145 - 3 Sqrt[2298])^(1/3)

    = 1.94484 + 1.60245 i

    x3=2/3 + (7 (1 - I Sqrt[3]))/(6 (145 - 3 Sqrt[2298])^(1/3)) +

    1/6 (1 + I Sqrt[3]) (145 - 3 Sqrt[2298])^(1/3)

    =1.94484 - 1.60245 i