test_stf

116 days ago by lonepsi

A = matrix(QQ, [[14,5,-2],[5,5,0],[-2,0,5]]) b = matrix(QQ, [[7],[7],[3]]) C, X, D = var('C,X,D') C = A^-1 X = A^-1*b D = A*A^-1*b A,b,C,X,D 
       
(
[14  5 -2]  [7]  [  5/41  -5/41   2/41]  [   6/41]  [7]
[ 5  5  0]  [7]  [ -5/41 66/205  -2/41]  [257/205]  [7]
[-2  0  5], [3], [  2/41  -2/41   9/41], [  27/41], [3]
)
(
[14  5 -2]  [7]  [  5/41  -5/41   2/41]  [   6/41]  [7]
[ 5  5  0]  [7]  [ -5/41 66/205  -2/41]  [257/205]  [7]
[-2  0  5], [3], [  2/41  -2/41   9/41], [  27/41], [3]
)
x = var('x') solve(x^2 + 3*x + 2, x) 
       
[x == -2, x == -1]
[x == -2, x == -1]
x, y = var('x,y') plot3d(x^2 + y^2, (x,-2,2), (y,-2,2)) 
       
20.0/14 
       
1.42857142857143
1.42857142857143
f(z) = z^5+z-1+1/z complex_plot(f,(-5, 5), (-5,5))