Originally Posted by

**joemc22** Hello, can anyone give me some help please!!

I'm struggling with the following question:

Output of a circuit current is given by: i1 + i2.

If i1 = 5sin(50t + pi/3) and i2 = 6cos 50t

Calculate the amplitude of i and the first time it occurs.

I have made a start but don't know if i'm going the right way? I have:

5sin(50t + pi/3) = (5x) sin50tcos pi/3 + cos50tsin pi/3

= 0.5 x sin50t + 0.866 x cos50t

Therefore: 6cos50t + 5sin(50t + pi/3) = 6cos50t + 5(0.5sin50t + 0.866cos50t)

Then I go on to find R and a, using arctan etc, but I don't think i'm going the right way, the inclusion of t is something I haven't come across in these sort of equations and is confusing me?

Hope this makes some sense and someone can point me in the right direction?

Thanks in advance.