Question

The 1st, 4th and 13th terms of AP., are in G.P. The first term is 3 ; find the A.P.​

Answer 1

Answer:

3,5,7,9... a=3 d=2

Step-by-step explanation:

first term is 3

now 4th term =

nth teen of an ap = a+(n-1)d

put n = 4

3 + 3d

now put n = 13

3 + 12d

now these three terms are in gp

so (3+3d)^2 = 3×(3+12d)

9+9d^2+ 18d = 9 + 36d

9d^2 = 18d

d^2 -2d=0

d cannot be equal to zero

so d=2

so ap is 3 5 7 9 11....