Question

\(M=2^2+4^2+6^2+...+50^2\)

Answer 1

M = 2² + 4² + 6² + ... + 50²

= (1.2)² + (2.2)² + (2.3)² + ...+(2.25)²

= 2².1². + 2².2² + 2².3² + ... + 2².25²

= 2².(1² + 2² + 3² + ... + 25²)

= 4.25.(25 + 1).(2.25 + 1) : 6

= 22100

Answer 2

ta có:

2^2+4^2+6^2+....+50^2 

= 2^2 . 1^2 + 2^2 . 2^2 + 2^2 . 3^2 + ....+2^2.25^2

= 2^2(1^2+2^2+3^2+...+25^2)

= 4.5525

=22100