Question

If the first term of an A.P. is a and nth term is b, then its common difference is

(a) $\frac{b-a}{n+1}$

(b) $\frac{b-a}{n-1}$

(c) $\frac{b-a}{n}$

(d) $\frac{b+a}{n-1}$

Answer 1

Here, we are given the first term of the A.P. as a and the n^th term (a_n) as b. So, let us take the common difference of the A.P. as d.

Now, as we know,

On substituting the values given in the question, we get.

Therefore,

Hence the correct option is (b).