Question

Write the expression of the common difference of an A.P. whose first term is a and nth term is b.

Answer 1

Here, we are given

First term = a

Last term = b

Let us take the common difference as d

Now, we know

a_n = a + (n-1)d

So,

For the last term (a_n),

      b = a + (n-1) d 

b - a = (n-1) d 

     ` d = (b-a)/(n-1)`

Therefore, common difference of the A.P. is  ` d = (b-a)/(n-1)`