Solutions des exercices

Exercices section 2.2.6

1. res = 0.
2. res = 0.
3. prod(1:5).
4. v=1 ./(1:10).
5. u=rand(1:10);u=u/sqrt(u*u') ou u=rand(1:10);u=u/sqrt(u.^2).
6. 2.^(1:8).
7. v=sin((1:20)*2*%pi/20).
8. v=v($:-1:1).
9. u=1:0.2:3.
10. u(5:5:$).

Exercices section 2.3.6

1. A=2*eye(10,10) ou A=diag(2*ones(1:10)).
2. B=A($:-1:1,:) ou B=A(:,$:-1:1).
3. C=rand(3,4)
   • C(:,[4 2 3 1]);
   • C(1:3,1:3)
   • [C;C].
4. • A=[ones(3,3), (2:4)' ; 1:4]
   • A=matrix(1:9,3,3) ou A=cumsum(ones(3,3))
   • A=ones(3,3);A([1,3],[1,3])=1
   • A=(1:4)';A=A(:,ones(1,4))
5. A=rand(4,4);B=rand(4,4);C=max(A,B).

Exercices section 2.4.5

1. A=rand(5,5);B=rand(A); M=A>B.
2. A=rand(5,5); A((A>0.3)&(A<0.7)).
3. A=rand(1,10);A(A>0.5)=A(A>0.5)-1
4. A=round(10*rand(5,5));find(A==0)

Exercices section 2.5.4

1. p=poly([1 1 3 -1],'x','c')
2. q=poly(1:3,'x'), roots(q)
3. n=25; q=poly(1:n,'x'), roots(q)
4. f=poly([0 1 -2],'x','c')/poly([-1,1],'x')
   • df=derivat(f)
   • y=horner(df,[0 2:4])
   • pol=roots(df('den'))

Exercices section 2.6.5

1. strcat(string(1:5),',')
2. strindex('bonjour','o'),strsubst('bonjour','o','-')
3. 'pi='+string(%pi)