Help w/ Circuit Theory: Complex Numbers & Voltage

[Toolkit]

Hi,

I'm working on an assignment for circuit theory, and I'm wondering if someone could let me know if I'm heading in the right direction?

1) I have a voltage value of 120 /_0 (polar form), from this can I assume that Arctan (a/b) =0, so voltage =120 in phase?

Therefore, V =120+J0, where V = a+jb

2) If I have a v = √2 x415cos(100πt) , basically can I say that "t = 0" , I end up with v = √2x415cos (0),

where Cos(0) = 1

is this correct, or am I missing something?

Thanks,

Colin

 

[trurle]

correct

 

[Baluncore]

You are heading in the right direction.
Check when you should be using Atan( a/b ), Atan( b/a ) or the Atan2( b, a ).