Question

find the sum of 51 terms of the A.P whose second term is 2 and the 4th term is 2

Answer 1

becaus second term and fourth term pc an ap is same therefore common difference will be 0.hence 51 term will also be 2.

sum will be 102

Answer 2

first term be a
common difference be d
second term =a + d
a+d =2.
a=2-d.



fourth term =a+ 3d
2=2-d+3d
2-2=2d
d=0/2
d=0



a=2-0
a=2

51 term
=a+50d
=2+0
51 term =2


sum of 51 terms =n/2(first term+ last term). (n=no.of terms)
=51/2(2+2)
=51/2×4
=51×2
=102


hope you got the answer if you are satisfied than pls mark it brainlist