Question

the 21 St term of AP 4½,-3 , 1½ _______4​

Answer 1

Answer:

a1=4½, A2=-3 and A3=1½

here,

common difference= a2 - a1 = -3-4½ = 15/2

also, a3-a2= 1½ - (-3) = 9/2

Since, a2 - a1 ≠ a3 - a2

Therefore the common difference is not same.

Hence the given series is not an AP and as it is not an AP , it's impossible to find the 21st term.