优优班--学霸训练营 > 知识点挑题
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            • 1.
              复数\(z\)满足\(z(1-2i)=3+2i\),则\( \overset{ .}{z}=(\)  \()\)
              A.\(- \dfrac {1}{5}- \dfrac {8}{5}i\)
              B.\(- \dfrac {1}{5}+ \dfrac {8}{5}i\)
              C.\( \dfrac {7}{5}+ \dfrac {8}{5}i\)
              D.\( \dfrac {7}{5}- \dfrac {8}{5}i\)
            • 2.

              已知\(z=1+i\).

              \((1)\)设\(\omega ={{z}^{2}}+3(1-i)-4\),求\(\omega \);

              \((2)\)如果\(\dfrac{{{z}^{2}}+az+b}{{{z}^{2}}-z+1}=1-i\),求实数\(a,b\)的值.

            • 3.

              已知复数\(z\)满足\(z+2i\)和\(\dfrac{z}{2-{i}}(i\)为虚数单位\()\)均为实数.

              \((1)\)求复数\(z\);

              \((2)\)若\(|z+mi|\leqslant 5\),求实数\(m\)的取值范围.

            • 4.

              已知\((a-i)^{2}=2i\),那么实数\(a=\)____\(.\) 

            • 5.

              \(i\)是虚数单位,复数\(z=a+i\left(a∈R\right) \)满足\({z}^{2}+z=1-3i \),则\(\left|z\right|= (\)   \()\)

              A.\(\sqrt{2}\)或\(\sqrt{5}\)
              B.\(2\)或\(5\)
              C.\(\sqrt{5}\)
              D.\(5\)
            • 6.

              已知复数\(z=1+i\).

              \((1)\)      若复数\(\omega ={{z}^{2}}+3\overline{z}-4\),求复数\(\omega \)的模长

              \((2)\)      如果\({{z}^{2}}+az+b=1-i\),求实数\(a,b\)的值.

            • 7.

              已知\(i\)为虚数单位,且\(\dfrac{2+i}{1+2i}=x+yi(x,y∈R)\),则\(|x+yi|=(\)    \()\)

              A.\(1\)
              B.\(\sqrt{2}\)
              C.\(\sqrt{3}\)
              D.\(2\)
            • 8.

              给出下列几个命题:

              \(①\)若\(x\)是实数,则\(x\)可能不是复数;
              \(②\)若\(z\)是虚数,则\(z\)不是实数;
              \(③\)一个复数为纯虚数的充要条件是这个复数的实部等于零;
              \(④-1\)没有平方根;
              \(⑤\)若\(a∈R\),则\((a+1)i\)是纯虚数;

              \(⑥\)两个虚数不能比较大小.

              则其中正确命题的个数为________.

            • 9.

              已知复数\(z=a+bi(a,b∈R)\),则\(z∈R\)的充要条件是 (    )

              A.\(a+bi=a-bi\)
              B.\(a+bi=-a+bi\)
              C.\(ab=0\)
              D.\(a=b=0\)
            • 10.
              已知实数\(m\),\(n\)满足\((m+ni)(4-2i)=3i+5\),则\(m+n=(\)  \()\)
              A.\( \dfrac {9}{5}\)
              B.\( \dfrac {11}{5}\)
              C.\( \dfrac {9}{4}\)
              D.\( \dfrac {11}{4}\)
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