Question

2 de sus va rooooog

Answer 1

$n \geq 2$
n ∈ N

$c_n^2 + c_{n+1}^2 = 36$
$\frac{n(n-1)}{2} + \frac{n(n+1)}{2} = 36$
$2n^2=72$
$n_1 = 6$
$n_2 = -6$ - Nu convine

S: {6}