Question

if the sum of first p terms of an A.P. is q and sum of q terms is p show that the sum of first p+q terms is -(p+q)

Answer 1

let first term is a
differences is d
now , a+(p-1)d =q ...... (1)
a+(q-1)d =p........ (2)

solving equ. 1 and 2
we g get the value of a and d

now put the value of a and d in this equ.
a+(p+q-1)d
u get the result