Fie Suma s cu donbandeade 10/100S
dy upa un an are S+10S/100=110S/100=1,1S
duopa al doilea an
1,1S + 1/10* 1,1S= 1,1*1,1 S=1,1² *s
dy upa al treila an
1,1² 8s+ 0,1 *1,1² *S= 1,1*1,1² * S= 1,1³*S
la liceu urmeaza demonstratie prin inductie
la gimanziu \
dupa al cincelea an
S* 1,1^5
in particular pt S=1000000
1 000 000*1,1^5=1 610 510lei
