2y^4+3y^3-16y^2+3y+2=0

来源:百度知道 编辑:UC知道 时间:2024/05/31 17:57:26
解方程

2y^4+3y^3-16y^2+3y+2=0
2y^4 - 4y^3 + 7y^3 - 14y^2 - 2y^2 + 4y - y +2 = 0
2y^3(y-2) + 7y^2(y-2) -2y(y-2) - (y-2) = 0
(y-2)(2y^3 + 7y^2 - 2y -1) = 0
(y-2)(2y^3 - y^2 + 8y^2 - 4y + 2y -1) = 0
(y-2)[y^2(2y-1) + 4y(2y-1) + (2y -1)] = 0
(y-2)(2y-1) (y^2 + 4y + 1) = 0
(y-2)(2y-1)[(y+2)^2 -3] = 0
(y-2)(2y-1)(y + 2 -√3)(y +2 +√3) = 0
所以
y1 =2
y2 = 1/2
y3 = -2 + √3
y4 = -2 - √3

nn