Calculating impedance for parallel circuit

[spiderabbit]

Hi there,

Below shows the solution to the circuit.
However i am confused about how to solve the eq in red box.

http://img208.imageshack.us/img208/2797/123vv.jpg

do i need to solve it by calculator or more work needs to be done?

If it's by calculator i am using sharp and i couldn't get the correct answer.

Please advice. Thanks.

 

[tiny-tim]

Welcome to PF!

Hi spiderabbit! Welcome to PF!

The trick for putting (a + ib)/(p + iq) into standard form is to myltiply both top and bootm by the complex conjugate of the bottom …

(a + ib)/(p + iq) = (a + ib)(p - iq)/(p² + q²)

That does give your answer of 4 + j8 … what is worrying you?