Question

Quanto é ( 2 + i )³ ?

Answer 1

Resposta : 11i + 2

Cálculo :

i² = -1

( 2 + i )³ = ( 2 + i ) • ( 2 + i ) • ( 2 + i )

= 4 + 2i + 2i + i² • ( 2 + i )

= 4 + 4i - 1 • ( 2 + i )

= ( 4i + 3 ) • ( 2 + 1 )

= 8i + 4i² + 6 + 3i

= 8i + 4 • ( -1 ) + 6 + 3i

= 11i - 4 + 6

= 11i + 2