Question

[Gummy 2982011]

help me !!!

who can do this help me tick!!!!

Thank you so much :))))

Answer 1

[Trần Hiếu Anh]

\(x\times\dfrac{20}{11}=\dfrac{1}{1}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\\ x\times\dfrac{20}{11}=\dfrac{10}{11}\\ \Rightarrow x=\dfrac{1}{2}\)

Answer 2

[Nguyễn Linh Đan]

Ta có :

=> X x 20/11 = ( 1 - 1/3 ) + ( 1/3 - 1/5 ) + ( 1/5 - 1/7 ) + ( 1/7 - 1/9 ) + ( 1/9 + 1/ 11 )

=> X x 2/11 = 1 - 1/11 = X x 1/11 = 11/11 - 1/11

=> X x 20/11 = 10/11

=> X = 10/11 : 20/11

=> X = 1/2