Question

C=100^2-99^2+98^2-97^2+......+2^2-1^2

Answer 1

 

C=100^2-99^2+98^2-97^2+......+2^2-1^2

=(100-99).(100+99)+(98-97)(98+97)+...+(2-1)(2+1)

=100+99+98+97+...+2+1

=\(\frac{\left(100+1\right).100}{2}=5050\)

Answer 2

C= 100² - 99² + 98² - 97² +...+ 2² - 1²

   = (100-99).(100+99) + (98-97).(98+97) +...+(2-1).(2+1)

   = 100 + 99 + 98 + 97 +...+ 2 + 1

   = (1+100).100 : 2

   = 5050

Answer 3

5050 là đúng đó