Cu elementele multimii M={1,3,5,7,9,.......,2n+1},construim submultimile:A1={1}, A2={3,5}, A3={7,9,11},....
a) Calculati suma elementelor multimii A6.
b) Calculati cardinalul multimii A1 U A2 U A3 U... U A20
a) A4={13,15,17,19} A5={21,23,25,27,29} A6={31,33,35,37,39,41} 31+33+35+37+39+41 =(41+31)*6/2 =72*3=216 b) A1 are un element, A2 2 elemente, ....A20 are doua elemente cardinalul reuniunilor este (1+2+3+...+20) =(20+1)*20/2 =21*10=210
