Question

The 6th term of an AP is 0.Prove that it's 21st term is triple it's 11th term​

Answer 1

Step-by-step explanation:

t6=a+5d

a+5d=0...(1)

t11=a+10d

i.e. t11=a+5d+5d...(2)

t21=a+20d

i.e. t21=a+5d+15d...(3)

But a+5d=0..(from (1) ).

t11=5d and t21=15d.

Hence t21=3t11

Answer 2

so this the process

NORMAL QUESTION