Question

Calculati suma
${2} + {2}^{2} + {2}^{3} + ... + {2}^{9}$
Ajutor!Multumesc!​

Answer 1

Explicație pas cu pas:

S=2+2²+...+2⁹ |*1/2

(-) scadem ambele parti

1/2S=1+2+...+2⁸

(S-1/2S)=-1+(2-2)+(2²-2²)+...+(2⁸-2⁸)+2⁹

1/2S=-1+2⁹ |*2

S=-2+2¹⁰=-2+(2⁵)²=-2+32²=-2+1024=1022