优优班--学霸训练营 > 知识点挑题
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            • 1.
              复平面内表示复数\(i(1-2i)\)的点位于\((\)  \()\)
              A.第一象限
              B.第二象限
              C.第三象限
              D.第四象限
            • 2.
              若将复数\( \dfrac {2+i}{i}\)表示为\(a+bi(a,b∈R,i\)是虚数单位\()\)的形式,则\( \dfrac {b}{a}\)的值为\((\)  \()\)
              A.\(-2\)
              B.\(- \dfrac {1}{2}\)
              C.\(2\)
              D.\( \dfrac {1}{2}\)
            • 3.
              设\(i\)为虚数单位,则\((1+i)^{5}\)的虚部为 ______ .
            • 4.
              已知复数\(z= \dfrac {3i+1}{1-i}\),则\(z\)的虚部是 ______ .
            • 5.
              已知\(a∈R\),且\( \dfrac {-a+i}{1-i}\)为纯虚数,则\(a\)等于\((\)  \()\)
              A.\( \sqrt {2}\)
              B.\(- \sqrt {2}\)
              C.\(1\)
              D.\(-1\)
            • 6.
              若复数\(z= \dfrac {a+3i}{1-2i}(a∈R,i\)是虚数单位\()\),且\(z\)是纯虚数,则\(|a+2i|\)等于\((\)  \()\)
              A.\( \sqrt {5}\)
              B.\(2 \sqrt {5}\)
              C.\(2 \sqrt {10}\)
              D.\(40\)
            • 7.
              设复数\(z\)满足\(z(2+i)=1-2i(i\)为虚数单位\()\),则\(|z|=\) ______ .
            • 8.
              设\(i\)是虚数单位,复数\( \dfrac {1+ai}{2-i}\)为纯虚数,则实数\(a=\) ______ .
            • 9.
              已知复数\(z_{1}=\sin x+λi,z_{2}=(\sin x+ \sqrt {3}\cos x)-i(λ,x∈R,i\)为虚数单位\()\).
              \((1)\)若\(2z_{1}=i⋅z_{2}\),且\(x∈(0, \dfrac {π}{2})\),求\(x\)与\(λ\)的值;
              \((2)\)设复数\(z_{1}\),\(z_{2}\)在复平面上对应的向量分别为\( \overrightarrow{OZ_{1}}, \overrightarrow{OZ_{2}}\),且\( \overrightarrow{OZ_{1}}⊥ \overrightarrow{OZ_{2}}\),\(λ=f(x)\),求\(f(x)\)的最小正周期和单调递减区间.
            • 10.
              已知复数\(z_{1}=2+i\),\(z_{2}=a+3i(a∈R)\),\(z_{1}⋅z_{2}\)是实数,则\(|z_{1}+z_{2}|=\) ______ .
            0/40

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