What is the square of n squared plus 2n minus 1?

Answer 1

(n2 + 2n - 1) (n2 + 2n - 1) = n4 + 2n3 - n2 + 2n3 + 4n2 - 2n - n2 - 2n + 1

= n4 + 4n3 + 2n2 - 4n + 1

try with n = 5:

(5 squared + 10 - 1) squared = 34 squared = 1156

with formula

(5^4) + (4 *(5^3)) + (2 * (5^2)) - (4 * 5) + 1

= 625 + 500 + 50 - 20 + 1

= 1156