ok thanks for the help

 

Just as you can express impedance as a complex number you can also express voltage and current waveforms in complex notation using the Euler Identity.

http://en.wikipedia.org/wiki/Euler's_identity

You should also review some material on Phasors

http://en.wikipedia.org/wiki/Phasors

that should keep you off the streets for at least an afternoon.

Don't forget to check the e-book pages on this forum
http://www.allaboutcircuits.com/worksheets/phasor.html
http://www.allaboutcircuits.com/vol_2/chpt_13/9.html
http://www.allaboutcircuits.com/vol_2/chpt_3/3.html
http://www.allaboutcircuits.com/vol_2/chpt_4/3.html