Question

how many terme of the series 1+4+16+........ to make the sum 1365​

Answer 1

a = 1

d = 4-1 = 3

Sum= 1365

We have to find n

Sum = n/2 ( 2a + (n-1) d )

1365 = n/2 ( 2 + 3n - 3 )

2730 = n ( -1 + 3n )

Now solve the quadratic equation formed and get your answer.

Hope it helps.

Please mark it as brainliest answer.