Question

find the middle term in an A.P ; -4,-2,0.............16 help me

Answer 1

the first term is -4 ie. a
common difference is 2
nth term is 16
= a+(n-1)d
16 = a+(n-1)d
16 = -4 + (n-1)d
20=( n-1) × 2
n-1 = 10
therefore n = 11
middle term is (n+1)/2 ,
11+1/2 = 6
6th term of the ap is a+5d
-4 + 5×2 = 6
therefore the answer is 6

Answer 2

d = t2-t1
=> -2-(-4)
=> -2+4
=> 2

n = l-a/d +1

=> 16-(-4)/2 +1
=> 16+4/2 +1
=> 20/2 +1
=> 10+1
=> 11

so, middle term = 6th term

t6 = a + (n-1) d
=> -4 + (6-1) 2
=> -4 + (5) 2
=> -4 + 10
=> 6

#Hassan