Question

The 4th term of an AP is zero.prove that the 25th term is 3times its 11th term

Answer 1

Hi Mate!!!

T4th = a + 3d

T25th = a + 24d.... equation 1

T11th = a + 10d ..... equation 2

Where d common difference and a is ist term.

T4th = 9 given.

=>. a = -3d

Now, put value of a in equation 1 and 2

T25th = 21d

and

T11th = 7d

=> T25th = 3 T11th { 21d = 3 ( 7d ) }