Question

sum of n terms is m and m terms in n.find sum of m+n.ans.fast​

Answer 1

Step-by-step explanation:

the final answer is Sm+n = -(m+n)

Answer 2

Let a be the first term and d be the common difference of the given AP. Then,

Sn=2n[2a+(n−1)d]

Given,

Sm=n

2m[2a+(m−1)d]=n

2am+m(m−1)d=2n          ...........(1)

Sn=m

2n[2a+(n−1)d]=m

2an+n(n−1)d=2m          ..........(2)

On subtracting 2 from 1, we get,

2a(m−n)+[(m2−n2)−(m−n)]d=2(n−m)

(m−n)[2a+(m+n−1)d]=2(n−m)

2a+(m+n−1)d=−2          ..........(3)

Sum of (m+n) terms of the given AP

Sm+n=2m+n[2a+(m+n−1)d]

           =2m+n(−2)

Hope this answer help you