Sequence & Progression

Q1:
If a,b,c are digits ,then rational number represented by 0.cababab.... is ?

Q2:
Calculate sum of products of ten numbers Â±1,Â±2,Â±3,Â±4,Â±5 taking two at a time.

Q3:
Sum of series 1√3+√7+1√7+√11+1√11+√15.....
a)√3+4n-√34
b)n√3+4n+√3
c)less than n
d)greater than √n2

8 Answers

2.
(0)^2=2(1^2+2^2+3^2+4^2+5^2)+2S\\ S=-55

3.take a general term multiply and divide by conjugate

1.
R=0.cababababab.........
10R=c+ab/99
R=c/10 +ab/990
edited

Explain 2)

2 is
(Î£a(i))^2=Î£a(i)^2+Î£(i<j)aiaj

3 is a,b,c

let me know if u want the solution

in ques 1) shouldn't it be
10R= c+ ab/99 ????

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