Question

Find the middle term of the ap -11,-7,-3,
.......45

Answer 1

Answer:

a=-11

d=-7-(-11)=4

last term=45

an=a+(n-1)+d

45=-11+(n-1)4

45+11=4n-4

56+4=4n

60/4=n

n=15

middle term=15+1/2=8

a8=a+(n-1)+d

a8=-11+(8-1)+4

a8=-11+7+4

a8=-11+11

a8=0

thanks hope i help you

Answer 2

Answer:

Given:

a = -11

d= -7-(-11) = 4

an = last term = 45

an = a+(n-1)*d (formula for Nth term of A.P)

45 = -11+(n-1)x4

-11 comes to L.H.S (Left Hand side) and becomes +11 so it be's like 45+11 = (n-1)x4

now we multiply in R.H.S (Right Hand Side) n&4 , 4&-1....   56 = 4xn-4

now take -4 to L.H.S....   56+4 = 4xn

now take 4 to denominator of L.H.S....   60/4 = n

n=15

now we got n = 15

middle term = 15+1/2 = 8

a8 = a+7d

a8 = -11+7x4 = -17

Therefore the middle term of the A.P is -17