Question

The first and last terms of an A.P. are a and b. There are altogether (2n + 1) terms. A new series is
formed by multiplying each of the first 2n terms by the next term. find the sum of the new series.

Answer 1

Answer:

first term = a

second term =b

So, common difference=d=b-a

Let nth term is the last term and which is 2a.

Then 2a=a+(n-1)d=a+(n-1)(b-a)

or,a=nb-b-an+a

or,a-a+b=nb-na

or,n(b-a)=b

or,n=b/(b-a)

Now the sum(S)=(a+2a)b/2(b-a)

=3ab/2(b-a) ans.

hope it helps

Answer 2

Answer:

Step-by-step explanation: