Question

Tính: 1)A=1³+2³+3³+….+99³+100³

2)B=2³+4³+6³+….+98³+100³

Answer 1

Bài 1:

\(A=1^3+2^3+...+99^3+100^3\)

\(=\left(1+2+...+100\right)^2\)

\(=\left[\frac{100\cdot\left(100+1\right)}{2}\right]^2\)

\(=5050^2=25502500\)

Answer 2

A= 1³ + 2³ + 3³ + ... + 100³

= 1 + 2 + 1.2.3 + 2.3.4 + ... + 100 + 99.100.101

= ( 1 + 2 + 3 + ... + 100) + ( 1.2.3 + 2.3.4 + ... + 99.100.101 )

= 5050 + 101989800

= 101994850