Question

the sum of first natural number is given by 1/2 n power 2 + 1/2 n find​

Answer 1

Answer:

S = n (n + 1 )2 231 = n (n + 1 )2 n2 + n - 462 = 0 n2 + 22n - 21n - 462 = 0 n (n + 22 ) - 21 (n + 22 ) = 0 (n + 22 ) (n - 21 ) = 0 n = - 22 or n = 21 n