Toán Lớp 6: A=1-2+3-4+5-6+...+97-98+99- B=1+2+2 ²+2 ³+...+2^2019 help me

Question

Toán Lớp 6:  A=1-2+3-4+5-6+...+97-98+99- B=1+2+2 ²+2 ³+...+2^2019 help me

behocgioitoan · Answer

A=1-2+3-4+5-6+...+97-98+99-100     A= ( 1-2) + (3-4) +(5-6)+...+(97-98)+(99-100)    Ta c&oacute; 100 : 2 = 50 cặp    => A = -1.50 = -50    B=1+2+2 &sup2;+2 &sup3;+...+2^2019               (1)     2B = 2+2&sup2;+2&sup3;+2^4 +.....+ 2^2020     (2)     Lấy (2) - (1) => B = 2^2020 - 1

hothaibinh · Answer

A=1-2+3-4+5-6+...+97-98+99-100     A= ( 1-2) + (3-4) +(5-6)+...+(97-98)+(99-100)    Ta c&oacute; 100 : 2 = 50 cặp    => A = -1.50 = -50    B=1+2+2 &sup2;+2 &sup3;+...+2^2019               (1)     2B = 2+2&sup2;+2&sup3;+2^4 +.....+ 2^2020     (2)     Lấy (2)        &minus;       (1) => B = 2^2020 -         (       -1)

Toán Lớp 6: A=1-2+3-4+5-6+…+97-98+99- B=1+2+2 ²+2 ³+…+2^2019 help me

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