Question

if n is equal to 2 n square minus 1 then the value of fourth term is ​

Answer 1

Answer:

14

Step-by-step explanation:

Given-

Sum(n) = 2n²-1           ---(1)

To find the fourth term we use the formula-- An = Sn - Sn-1

Therefore 4th term = S4 - S3

                                = 2(4)²-1  - ( 2(3²)-1  )

                               = 2x16 - 1   - 2x9  - 1

                              = 32-1  - 18 - 1

                             = 31 - 17

                          = 14