Question

) Cho B = 12/(2.4)2 + 20/(4.6)2 +  … 388/(96.98)2 + 396/(98.100)2. Hãy so sánh B với 1/4

Answer 1

B=\(\frac{12}{2^2.4^2}+\frac{20}{4^2.6^2}+......+\frac{388}{96^2.98^2}+\frac{396}{98^2.100^2}\)

   =\(\frac{1}{2^2}-\frac{1}{4^2}+\frac{1}{4^2}-\frac{1}{6^2}+...+\frac{1}{96^2}-\frac{1}{98^2}+\frac{1}{98^2}-\frac{1}{100^2}\)

   =\(\frac{1}{2^2}-\frac{1}{100^2}\)

   =\(\frac{2599}{10000}< \frac{2500}{10000}=\frac{1}{4}\)

     => B<\(\frac{1}{4}\)

Answer 2

Bn ơi ! 1/2² - 1/100² là 2499/10000 chứ bn

Answer 3

SOs