Question

The 4th term of an ap is zero.prove that the 25th term of the ap is three times its 11th term

Answer 1

Solution: -

4th tem= a+ 3d

=>a + 3d = 0

=>a = -3d .... (1)

a11 = a + 10d

= -3d + 10d [using 1]

=7d ..... (2)


NOW,,,a25 = a + 24d

= -3d + 24d = 21 ..... (3)

2 is 3 times of 3..

so,,it is provrd.☺