Question

in a certain ep 32 term is twice the 12th term prove that 70 term is twice the 31st term

Answer 1

Given:

2(a12)=a32

To prove:

2(a31)=a70

an=a+(n-1)d

2(a+11d)=a+31d

2a+22d=a+31d

a=9d.........1

a31=a+30d

=9d+30d (from1)

=39d.......2

a70=a+69d

=9d+69d

=78d

=2(39d)

=2(a31)

Hence proved

Hpe it hlps u

Answer 2

Answer:

Step-by-step explanation:

32th term = a+31d

12th term = a+11d

Given condition

a+31d=2(a+11d)

a+31d = 2a+22d

a=9d

Prove

70th term = 2(31st term)

70th term= a+69d

= 9d+69d

=78d

31st term = a+30d

=39d

78d = 2(39d)

78d =78d

Hence prooved