Question

If x < 0 is a real number, then arg (x) = ____________.

Answer 1

If x < 0
i.e z = x + i 0 and x is negative
$\Rightarrow \theta ={\tan }^{-1}\left|\frac{0}{x}\right|={\tan }^{-1}0=0$
Hence, z lies in II quadrant chg z = π.