Hello AshwinBabu,

You asked a great question about the argument of a complex number. The principal argument of a complex number is from -π to π as you said. Itcan also be said that it’s equivalent to having it from 0 to 2π.

Actually sin (3π) will also give the same values as sin (π) and sin (2π). So we can write it that way. But to avoid confusion, we take only one rotation (and by default we say its from -π to π). It’s just a way of saying something…

I hope it’s clear. If not, you can WhatsApp truemaths at 8477885599. Or post another question on this portal.