Lời giải:
$1+\frac{1}{2}(1+2)+\frac{1}{3}(1+2+3)+...+\frac{1}{16}(1+2+3+...+16)$
$=1+\frac{1}{2}.\frac{2.3}{2}+\frac{1}{3}.\frac{3.4}{2}+....+\frac{1}{16}.\frac{16.17}{2}$
$=1+\frac{3}{2}+\frac{4}{2}+....+\frac{17}{2}$
$=\frac{2+3+4+...+17}{2}=\frac{1+2+3+...+17}{2}-\frac{1}{2}=\frac{17.18}{2.2}-\frac{1}{2}=76$
Tính nhanh A = 1+1/2(1+2)+1/3(1+2+3)+1/4(1+2+3+4)+...+1/16(1+2+3+...+16)
tính nhanh A= 1+1/2(1+2) +1/3(1+2+3)+1/4(1+2+3+4)+...+ 1/16(1+2+3+...+16)
b tính nhanh A= 1+1/2(1+2) +1/3(1+2+3)+1/4(1+2+3+4)+...+ 1/16(1+2+3+...+16)
Tính nhanh:
A = 1+ 1/2(1+2) + 1/3+(1+2+3) +1/4(1+2+3+4)+.....+1/16(1+2+3+....+16)
Tính nhanh
A=1+1/2[1+2]+1/3[1+2+3]+1/4[1+2+3+4]+...+1/16[1+2+3+...+16]
Tính nhanh
A= 1+ 1/2 (1+2) +1/3 (1+2+3) +1/4 (1+2+3+4) +...+ 1/16 (1+2+3+4+...+16)
Tính Nhanh
A=1+1/2[1+2]+1/3[1+2+3]+1/4[1+2+3+4]+...+1/16[1+2+3+...+16]
Tính nhanh: A = 1 + 1/2 . (1 + 2 ) + 1/3 . ( 1 +2+3) + ... + 1/16 ( 1+2+3+4+...+16)
Mong mọi người giúp đỡ!!!
tính nhanh
1+1/2(1+2)+1/3(1+2+3)+1/4(1+2+3+4)+....+1/16(1+2+3+4+...+16)