Answer:
The 4th term = a+3d = 0,
or a = -3d.
The 25th term = a+24d = -3d+24d = 21d. ...
the 25th term is 3 times the 11th term. Proved.
Answer:
a^25 = 3 x a^11 .
Step-by-step explanation:
Given a^4 = 0
That is (a + 3d) = 0
⇒ a = - 3d ........... (1)
nth term of AP is given by an = a + (n – 1)d
a^11 = a + 10d = – 3d + 10d = 7d [From (1)]
a^25 = a+ 24d = – 3d + 24d = 21d [From (1)]
Hence
The answer is a^25=3 x a^11
