14-Oct-2013


1> eps
ans = 2.2204e-016


2> format long


3> eps
ans = 2.22044604925031e-016


4> 2^(-52)
ans = 2.22044604925031e-016


5> 1 + eps
ans =  1.00000000000000


6> if (1 + eps == 1) disp('si') else disp('no') end
no


7> if (1 + eps/2 == 1) disp('si') else disp('no') end
si


8> eps/2
ans = 1.11022302462516e-016


9> realmin
ans =  2.22507385850720e-308


10> realmin^2
ans = 0


11> pwd()
ans = C:\cygwin\home\achilles


12> x = 1.e-15
x = 1.00000000000000e-015


13> ((x + 1) -1)/x
ans =  1.11022302462516


14> x = [-2 -1 0 1 2]
x =

  -2  -1   0   1   2



15> y = 2 .^ x
y =

   0.250000000000000   0.500000000000000   1.000000000000000   2.000000000000000   4.000000000000000



16> format


17> y = 2 .^ x
y =

   0.25000   0.50000   1.00000   2.00000   4.00000



18> plot(x,y)


19> x = linspace(-2,2)
x =

 Columns 1 through 10:

  -2.000000  -1.959596  -1.919192  -1.878788  -1.838384  -1.797980  -1.757576  -1.717172  -1.676768  -1.636364

 Columns 11 through 20:

  -1.595960  -1.555556  -1.515152  -1.474747  -1.434343  -1.393939  -1.353535  -1.313131  -1.272727  -1.232323

 Columns 21 through 30:

  -1.191919  -1.151515  -1.111111  -1.070707  -1.030303  -0.989899  -0.949495  -0.909091  -0.868687  -0.828283

 Columns 31 through 40:

  -0.787879  -0.747475  -0.707071  -0.666667  -0.626263  -0.585859  -0.545455  -0.505051  -0.464646  -0.424242

 Columns 41 through 50:

  -0.383838  -0.343434  -0.303030  -0.262626  -0.222222  -0.181818  -0.141414  -0.101010  -0.060606  -0.020202

 Columns 51 through 60:

   0.020202   0.060606   0.101010   0.141414   0.181818   0.222222   0.262626   0.303030   0.343434   0.383838

 Columns 61 through 70:

   0.424242   0.464646   0.505051   0.545455   0.585859   0.626263   0.666667   0.707071   0.747475   0.787879

 Columns 71 through 80:

   0.828283   0.868687   0.909091   0.949495   0.989899   1.030303   1.070707   1.111111   1.151515   1.191919

 Columns 81 through 90:

   1.232323   1.272727   1.313131   1.353535   1.393939   1.434343   1.474747   1.515152   1.555556   1.595960

 Columns 91 through 100:

   1.636364   1.676768   1.717172   1.757576   1.797980   1.838384   1.878788   1.919192   1.959596   2.000000



20> x = linspace(-2,2);


21> size(x)
ans =

     1   100



22> length(x)
ans =  100


23> y = 2 .^ x;


24> length(y)
ans =  100


25> plot(x,y)


26> hold on


27> y3 = 3 .^ x;


28> plot(x,y3, 'r')


29> axis equal


30> axis equal off


31> yexp = exp(x);


32> plot(x,yexp, 'g')


33> axis on


34> grid on


35> exp(1)
ans =  2.7183


36> format long


37> e
ans =  2.71828182845905


38> pi
ans =  3.14159265358979


39> % occorre caricare la funzione costante
% http://www.dm.unibo.it/~achilles/calc/programmi/N_A.m

urlwrite("http://www.dm.unibo.it/~achilles/calc/programmi/N_A.m","N_A.m")

39> N_A
ans = 6.02214179000000e+023


40> hold off


41> x = linspace(1-1.e-5,1+1.e-5);


42> y = (x - 1).^3;


43> yy = x.^3 - 3*x.^2 + 3*x -1;


44> plot (x,y)


45> hold on


46> plot (x,yy, 'r')


47> hold off


48> quit