day1/cheatsheet6.tex
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     1 \documentclass[12pt]{article}
       
     2 \title{Solving Equations \& ODEs}
       
     3 \author{FOSSEE}
       
     4 \begin{document}
       
     5 \date{}
       
     6 \vspace{-1in}
       
     7 \begin{center}
       
     8 \LARGE{Solving Equations \& ODEs}\\
       
     9 \large{FOSSEE}
       
    10 \end{center}
       
    11 \section{Solving linear equations}
       
    12 \begin{verbatim}
       
    13     In []: A = array([[3,2,-1],
       
    14                       [2,-2,4],                   
       
    15                       [-1, 0.5, -1]])
       
    16     In []: b = array([[1], [-2], [0]])
       
    17     In []: x = solve(A, b)
       
    18     In []: Ax = dot(A,x)
       
    19     In []: allclose(Ax, b)
       
    20     Out[]: True
       
    21 \end{verbatim}
       
    22 \section{Finding roots}
       
    23 \begin{verbatim}
       
    24   In []: coeffs = [1, 6, 13]
       
    25   In []: roots(coeffs)
       
    26 \end{verbatim}
       
    27 Finding the roots of a function
       
    28 \begin{verbatim}
       
    29 In []: fsolve(sin(x)+cos(x)**2, 0)
       
    30 \end{verbatim}
       
    31 \section{ODE}
       
    32 \begin{verbatim}
       
    33   In []: def epid(y, t):
       
    34   ....     k, L = 0.00003, 25000
       
    35   ....     return k*y*(L-y)
       
    36   ....
       
    37   
       
    38   In []: t = arange(0, 12, 0.2)
       
    39 
       
    40   In []: y = odeint(epid, 250, t)
       
    41 
       
    42   In []: plot(t, y)
       
    43 \end{verbatim}
       
    44 \end{document}