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1/Z1 = 1/\(\displaystyle \sqrt{5}\) * [2 + j]
Oooops ... going to the corner for 5 minutes with Jomo (permanent resident) and the spider.Good advice, but there's no need for the root in this case...
[math] \frac{1}{Z_1} = \frac{1}{\left(2-j\right)} = \frac{\color{red}{2+j}}{\left(2-j\right)\left(\color{red}{2+j}\right)} = \frac{2+j}{2^2+1}= \frac{2+j}{5} [/math]