小编slo*_*oan的帖子

我使用python和Sympy很新...并且使用sympy解决了多变量不等式问题.

假设我在文件中有很多函数,如下所示:

    cst**(sqrt(x)/2)/cst
    exp(sqrt(cst*x**(1/4)))
    log(log(sqrt(cst + exp(x))))
    (y**(1/4) + y)**cst
    sqrt(y/log(x))/cst
    sqrt(cst**log(cst) + x)
    (y**2)**(x/4)
    sqrt(y*sqrt(cst**y))
    log(sqrt(2)*sqrt(cst)*x)

我需要派生它们,设置常量的值并检查是否,对于每个函数f,

    df/dx > 0
    df/dy < 0 

x在[0,+ oo]中,y在[0,1]中.

推导我使用:

    dx = diff(f, x)
    dy = diff(f, y)

然后当我尝试:

    cst = 2 #(for example) 
    solve(dx > 0) 

我收到了这个错误:

    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/usr/local/lib/python2.7/dist-packages/sympy/solvers/solvers.py", line 634, in solve
symbols=symbols)
    File "/usr/local/lib/python2.7/dist-packages/sympy/solvers/inequalities.py", line 374, in reduce_inequalities
    raise NotImplementedError("only univariate inequalities are supported")
    NotImplementedError: only univariate inequalities are …