一个数学方程式求解: 2^(x-3) = x - V2EX
eric_zyh

一个数学方程式求解: 2^(x-3) = x

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  •   eric_zyh Feb 10, 2012 5465 views
    This topic created in 5204 days ago, the information mentioned may be changed or developed.
    数学都忘的差不多了。遇到一个这样的方程,用数学方法能解开么?

    2^(x-3) = x
    14 replies    1970-01-01 08:00:00 +08:00
    c
        1
    c  
       Feb 10, 2012
    x-3 = log2(x)

    只能画图大致求交点的区间,做选择题应该没问题,精确值应该用mathlab了吧。。
    cutehalo
        3
    cutehalo  
       Feb 10, 2012
    超越方程如果不是特殊的话一般都不能得到解析解,只有数值解和近似解。可以用matlab来求
    zhigang1992
        4
    zhigang1992  
       Feb 10, 2012
    @est 好网站,呵呵
    eric_zyh
        5
    eric_zyh  
    OP
       Feb 10, 2012
    @est 这个真心好
    atempcode
        6
    atempcode  
       Feb 11, 2012
    @est 好站, 开眼界了
    bruce
        7
    bruce  
       Feb 11, 2012 via Android
    v2ex高中生这么多了。
    wzxjohn
        8
    wzxjohn  
       Feb 11, 2012
    @est 好站!!!
    haichong520
        9
    haichong520  
       Feb 11, 2012
    擦、全忘了!
    est
        10
    est  
       Feb 11, 2012
    Wolfram|Alpha就是mathematica公司做的在线版,功能很强大的。只不过我一般用它来看汇率和单位换算~~~
    fline
        11
    fline  
       Feb 11, 2012
    @est 开眼了 好网站
    guoquan
        12
    guoquan  
       Feb 11, 2012
    @est 应该说mathematica是Wolfram公司的吧

    它是当年风靡一时现在继续风靡的智能搜索平台了
    est
        13
    est  
       Feb 11, 2012
    @guoquan
    Matrix24
        14
    Matrix24  
       Apr 12, 2014
    输入:Solve[2^(x - 3) == x, x]
    结果:{{x -> -(ProductLog[-(Log[2]/8)]/Log[2])}, {x -> -(
    ProductLog[-1, -(Log[2]/8)]/Log[2])}}
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