Question

1^2+3^2+,...+199^2

 

Answer 1

\sum_1^199 x^{2}=2646700

Answer 2

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http://www.hostmath.com/ copy cong thuc roi bam chu A o tren

Answer 3

2644700 là đáp án đúng

ai tích mình là cao thủ

Answer 4

\(\frac{199\left(199+1\right)\left(2.199+1\right)}{6}=2646700\)

Answer 5

ban lam ho minh

Answer 6

B=1²+2²+3²+4²+...+199²

=1+2+3+4+...+199+(1.2+2.3+3.4+...+198.199)

đặt A=1.2+2.3+3.4+...+198.199

=>3A=1.2.3+2.3.3+3.4.3+...+198.199.3

=1.2.3+2.3.4-1.2.3+3.4.5-2.3.4+...+198.199.200-197.198.199

=198.199.200

=>A=7880400

=>B=19900+7880400=7900300

Answer 7

lacde roi