Répondre :
1)[tex] 2^{n} = 2 * 2^{n} - 2^{n} = 2^{n+1} - 2^{n} [/tex]
2) S = [tex] 2^{0} + 2^{1} + ........ + 2^{n} = (2^{1} - 2^{0}) + (2^{2} - 2^{1}) + ..... + (2^{n+1} - 2^{n}) [/tex]
3) S = [tex] 2^{n+1} - 2^{0} = 2^{n+1} - 1[/tex]
2) S = [tex] 2^{0} + 2^{1} + ........ + 2^{n} = (2^{1} - 2^{0}) + (2^{2} - 2^{1}) + ..... + (2^{n+1} - 2^{n}) [/tex]
3) S = [tex] 2^{n+1} - 2^{0} = 2^{n+1} - 1[/tex]