Question

If a = 1 + i, then a² equals

Options

• 1 − i

•  2i

•  (1 + i) (1 − i)

• i − 1.

Answer 1

 2i

 a = 1 + i                   
On squaring both the sides, we get,
a² = (1 + i)²

\[\Rightarrow\] a²  = 1 + i²  + 2i

\[\Rightarrow\] a² = 1 \[-\] 1 + 2i ( ∵ i² = \[-\] 1)

\[\Rightarrow\]  a²  = 2i