作业帮用mathematica求解方程Solve[8 Cos[0.5x] - 4x Sin[0.5x] == 0, x] 出不来答案,是咋么回事显示Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >>
来源：学生作业帮助网 编辑：作业帮 时间：2024/07/30 12:20:09
![用mathematica求解方程Solve[8 Cos[0.5x] - 4x Sin[0.5x] == 0, x] 出不来答案,是咋么回事显示Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >>](/uploads/image/z/4346736-24-6.jpg?t=%E7%94%A8mathematica%E6%B1%82%E8%A7%A3%E6%96%B9%E7%A8%8BSolve%5B8+Cos%5B0.5x%5D+-+4x+Sin%5B0.5x%5D+%3D%3D+0%2C+x%5D+%E5%87%BA%E4%B8%8D%E6%9D%A5%E7%AD%94%E6%A1%88%2C%E6%98%AF%E5%92%8B%E4%B9%88%E5%9B%9E%E4%BA%8B%E6%98%BE%E7%A4%BASolve%3A%3Atdep%3A+The+equations+appear+to+involve+the+variables+to+be+solved+for+in+an+essentially+non-algebraic+way.+%3E%3E)
用mathematica求解方程Solve[8 Cos[0.5x] - 4x Sin[0.5x] == 0, x] 出不来答案,是咋么回事显示Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >>
用mathematica求解方程Solve[8 Cos[0.5x] - 4x Sin[0.5x] == 0, x] 出不来答案,是咋么回事
显示Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >>
用mathematica求解方程Solve[8 Cos[0.5x] - 4x Sin[0.5x] == 0, x] 出不来答案,是咋么回事显示Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >>
Solve和NSolve都是求解多项式方程的,对于大多数超越方程来说,只能用迭代法或者割线法求解,此时要用FindRoot函数.
用Plot[8 Cos[0.5 x] - 4 x Sin[0.5 x] == 0,{x,-20,20}]可以看出,这个方程应该有无数个根,看你需要的是哪一个.比如从图像上看,在2附近有一个根且比2小,如果这正是你需要的,可以运行
FindRoot[8 Cos[0.5 x] - 4 x Sin[0.5 x] == 0,{x,2}]
或者
FindRoot[8 Cos[0.5 x] - 4 x Sin[0.5 x] == 0,{x,1,2}]
前者用的迭代法,后者用的割线法.运行结果都为
{x -> 1.72067}
想要更高的精度可以通过调整机器计算精度实现.
其他位置的根情况类似.
楼上解释的真TM详细....这问题还TM是没有悬赏的！