Question

Matlab求解一元四次方程，谢谢！！

请直接写出所有实数解！谢谢

Answer 1

答案没有粘贴完全，

你在命令框输入：

>> syms R

>> solve(6977.7792*R^4-751430.4*R^3+70000*R^2-390625*R)

实数解一共是两个，一个0和

 680845638625332715761481677498105856/(529756883110557644360837902697025*((149675922774940285412833611695298148081345414208526763610103387^(1/2)*384562673712771586963165721542307835739384084140351305112407244800000^(1/2))/149675922774940285412833611695298148081345414208526763610103387 + 562128555737643094501877136546935000795176031009898496/12193121805393160895800021621464166335833373878625)^(1/3)) + ((149675922774940285412833611695298148081345414208526763610103387^(1/2)*384562673712771586963165721542307835739384084140351305112407244800000^(1/2))/149675922774940285412833611695298148081345414208526763610103387 + 562128555737643094501877136546935000795176031009898496/12193121805393160895800021621464166335833373878625)^(1/3) + 826206462264370816/23016448099360545

你自己看下吧^^

Answer 2

R=-0.7724741453709
R=107.5958567054726

追问

验算了，不对。。。

Answer 3

a=[6977.7792 -751430.4 70000 0 -390625];
b=roots(a)
b =

1.0e+002 *

1.075958567054725
0.004328327771162 + 0.006972773201798i
0.004328327771162 - 0.006972773201798i
-0.007724741453709

按多项式求解即可。