WAEC - Mathematics (2013 - No. 5)
If Un = n(n2 + 1), evaluate U5 - U4
18
56
62
80
Explicació
Un = n(n2 + 1)
U5 = 5(2 + 1)
= 5(25 + 1)
= 5(26) = 130
U4 = 4(42 + 1) = 4(16 + 1)
= 4(17) = 68
U5 - U4 = 130 - 68
= 62
U5 = 5(2 + 1)
= 5(25 + 1)
= 5(26) = 130
U4 = 4(42 + 1) = 4(16 + 1)
= 4(17) = 68
U5 - U4 = 130 - 68
= 62