The Fourth term of an A.P. is ten times the first. Prove that the sixth term is four times the second term.

Asked by sarika vijay kumar | 6th Sep, 2011, 05:34: PM

Expert Answer:

The formula for nth term of an A.p is a+(n-1)d,where a is the first term,d is the common difference.
Given,4th term=10 a.
=>10a=a+(4-1)d--(1)
=>9a=3d
=>d=3a---(2)
now,sixth term=a+(6-1)d
=>a+5d
=>a+5(3a)=16a
Thus,sixth term=4(4a)=4(2nd term)

Answered by  | 6th Sep, 2011, 06:32: PM

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