dobinda compusa = Suma · [ ( 1+p%) ^n -1 ]
precizare : paranteza rotunda la puterea n
n= numarul de ani
dodinda=4000 ·[ ( 1+ 3,5%)^( 8 ) -1]=
= 4000 · [ ( 1,035 )^(8) -1 ]
1,035²=1,07
1,07²=1,14
1.14²=1,31
dobinda = 4000 ·( 1,31 -1) = 4000 · 0,31=1240