Question

In an A. P fist term=a, difference is d, last term is l, find the term before last

Answer 1

Answer:

First term = a

Common difference = d

Last term = l

Term just before last = l-d (eq.)

We know that,

l=a+(n-1)d

Substituting value of l in above eq.,

l-d = a+(n-1)d -d  = a + dn - d - d = a+dn-2d = a+d(n-2) Ans.