Tính:
4+12+24+40+...+19404+19800=?
A=4+12+24+40+...19404+19800
a=4+12+24+40+...+19404+19800
A=4+12+24+40+...+19404+19800
tính tổng sau
4+12+24+40+....+19404+19800
Cho E = 4 + 12 + 24 + 40 +...+ 19404 + 19800
Tính E.
tính:
4+12+24+40+...+19404+19800
4+12+24+40+...+19404+19800=???
4+12+24+40+...+19404+19800