JEE MAIN - Mathematics (2008 - No. 25)
The conjugate of a complex number is $${1 \over {i - 1}}$$ then that complex number is :
$${{ - 1} \over {i - 1}}$$
$${1 \over {i + 1}}\,$$
$${{ - 1} \over {i + 1}}$$
$${1 \over {i - 1}}$$
คำอธิบาย
$$\left( {{1 \over {i - 1}}} \right) = {1 \over { - i - 1}} = {{ - 1} \over {i + 1}}$$