JEE MAIN - Mathematics (2008 - No. 25)

The conjugate of a complex number is $${1 \over {i - 1}}$$ then that complex number is :

$${{ - 1} \over {i - 1}}$$

$${1 \over {i + 1}}\,$$

$${{ - 1} \over {i + 1}}$$

$${1 \over {i - 1}}$$

$$\left( {{1 \over {i - 1}}} \right) = {1 \over { - i - 1}} = {{ - 1} \over {i + 1}}$$