Question

\(\dfrac{3}{2^2}\) . \(\dfrac{8}{3^2}\) . \(\dfrac{15}{4^2}\) ...\(\dfrac{99}{10^2}\)

Answer 1

\(\dfrac{2}{2^2}.\dfrac{8}{3^2}.\dfrac{15}{4^2}...\dfrac{99}{10^2}\)

=\(\dfrac{1.3}{2.2}.\dfrac{2.4}{3.3}.\dfrac{3.5}{4.4}...\dfrac{9.11}{10.10}\)

=\(\dfrac{1.2.3...9}{2.3.4...10}.\dfrac{3.4.5...11}{2.3.4...10}\)

Rút gọn biểu thức, ta được:

=\(\dfrac{1}{10}\).\(\dfrac{11}{2}\)

=\(\dfrac{11}{22}\)

=\(\dfrac{1}{2}\)

Answer 2

\(goiA=\dfrac{3}{2^2}.\dfrac{8}{3^2}......\dfrac{99}{10^2} \)

\(A=\dfrac{1.3}{2.2}.\dfrac{2.4}{3.3}.......\dfrac{9.11}{10.10}\)

\(A=\dfrac{31}{30}.\dfrac{1}{2}\)

\(A=\dfrac{31}{60}\)

Answer 3

NHẦM A=\(\dfrac{1}{2}.\dfrac{11}{10}\)

Answer 4

A=\(\dfrac{11}{20}\)

VẬY.....