If the ratio of the sum of m terms and n terms of an A.p be m2 :n2, prove that the ratio of mth and nth terms is (2m_1): (2n_1).
Answers
Answered by
1
Answer:
very easy just have to equate and apply the formula s=n/2[2a+(n-1) d]
Answered by
3
Answer:
Step-by-step explanation:
Sum of m terms of an A.P. = m/2 [2a + (m -1)d]
Sum of n terms of an A.P. = n/2 [2a + (n -1)d]
m/2 [2a + (m -1)d] / n/2 [2a + (n -1)d] = m2 : n2
⇒ [2a + md - d] / [2a + nd - d] = m/n
⇒ 2an + mnd - nd = 2am + mnd - md
⇒ 2an - 2am = nd - md
⇒ 2a (n -m) = d(n - m)
⇒ 2a = d
Ratio of m th term to n th term:
[a + (m - 1)d] / [a + (n - 1)d]
= [a + (m - 1)2a] / [a + (n - 1)2a]
= a [1 + 2m - 2] / a[1 + 2n -2]
= (2m - 1) / (2n -1)
Similar questions