Question

Tính:  A=1+1/2(1+2)+1/3(1+2+3)+....+1/16(1+2+3+....+16)

Answer 1

\(A=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{16}\left(1+2+3+...+16\right)\).

\(A=1+\frac{1}{2}.3+\frac{1}{3}.6+....+\frac{1}{16}.136\)

\(A=1+1,5+2+...+8,5\)

\(A=\frac{\left(8,5+1\right)\left[\left(8,5-1\right):0,5+1\right]}{2}=76\)

Answer 2

A = 1 + 1/2 x 2x3/2 + 1/3 x 3x4/2 +.............+ 1/16 x 16x17/2

A = 1+ 3/2 +4/2 + ............+ 17/2

A = 1+ (3+4+5+.........+17)/2

A = 1+75 = 76

Answer 3

1+2+3x(-2)+4x(1+2+3)+...+16x(1+2+3+...+15)

Answer 4

làm khó hiễu thế

Answer 5

A=1+3/2+2+...+17/2

A=2/2+3/2+4/2+...+17/2

A=(2+3+4+5+...+17)/2=144/2=76

Answer 6

giup to bai vat li