SSC
Government Jobs Exams
Numerical Ability
Arithmetic
sqrt (7* sqrt(7* sqrt (7*...)))=(343)^(y-1) then y is euqal to
a) 2/3 b) 1 c) 4/3 d) 3/4
Read Solution (Total 3)
-
- let sqrt (7* sqrt(7* sqrt (7*...)))=x
=>x=sqrt(7*x)
=>x^2=7x
=>x^2-7x=0
=>x=0,7
neglect 0, x=7
now 7 = (343)^(y-1)
=> (7^3)^(1/3)= (343)^(y-1)
=> (343)^(1/3)= (343)^(y-1)
=> (1/3)=(y-1)
=> 3y-3=1
=> 3y=4
=> y=4/3 ans - 12 years agoHelpfull: Yes(7) No(0)
- Trick:-- sqrt (p* sqrt(p* sqrt (p*...)))= p
P=7
then, sqrt (7* sqrt(7* sqrt (7*...))= (343)^(y-1)
====> 7 = (343)^(y-1)
====> 7 = 7^3(y-1)
====> 1=3(y-1)
====> y=4/3 - 12 years agoHelpfull: Yes(4) No(0)
- Sqrt(a*sqrt(a*(sqrt(a*..........)))=a [ According to the Rules of Surds]
Therefore,
sqrt(7 *(sqrt 7 *(sqrt 7 *.......)))= 7
=>7=(343)^(y-1)
=>7^1=(7^3)^(y-1)
=>1=3y-3 [since base is equal in both sides]
=>y=4/3. - 7 years agoHelpfull: Yes(0) No(0)
SSC Other Question