Problem

复数 $z=\frac{1}{2+i}$ (其中 $i$ 为虚数单位) 的虚部为

Answer

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Answer

Finally, the imaginary part of the complex number $z=\frac{1}{2+i}$ is \(\boxed{-\frac{1}{3}}\)

Steps

Step 1 :First, we multiply the numerator and denominator by the conjugate of the denominator, which is $2-i$.

Step 2 :\(z = \frac{1}{2+i} \times \frac{2-i}{2-i}\)

Step 3 :\(z = \frac{2-i}{(2+i)(2-i)}\)

Step 4 :\(z = \frac{2-i}{2^2 + i^2}\)

Step 5 :\(z = \frac{2-i}{4 - 1}\)

Step 6 :\(z = \frac{2-i}{3}\)

Step 7 :Finally, the imaginary part of the complex number $z=\frac{1}{2+i}$ is \(\boxed{-\frac{1}{3}}\)

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