Concept: Let z=x+iy be a complex number. Argument: - argz=arg(x+iy)=θ=tan−1(
y
x
) Note: - Principal argument (θ) ranges −π<θ≤π Calculation: Given: z=−1−i As z lies in third quadrant so arg (z)=−π+θ arg(−1−i)=−π+tan−1(−1∕−1) =−π+tan−1(1) =−π+π∕4 =−3π∕4