共50条信息
设\(z\)是虚数,\(ω=z+\dfrac{1}{z}\)是实数,且\(-1 < ω < 2\)
\((1)\)求\(|z|\)的值及\(z\)的实部的取值范围;
\((2)\)设\(u=\dfrac{1-z}{1+z} \),求证:\(u\)为纯虚数;
\((3)\)求\(ω-u^{2}\)的最小值
复数\(z=\left( 1-i \right){{a}^{2}}-3a+2+i(a\in R)\),
\((1)\)若\(z\)为纯虚数,求\(z\);
\((2)\)若在复平面内复数\(z\)对应的点在第三象限,求\(a\)的取值范围.
若虚数\(z\)同时满足下列两个条件:\(①z+\)\( \dfrac{5}{z}\)是实数;\(②z+3\)的实部与虚部互为相反数.这样的虚数是否存在?若存在,求出\(z\);若不存在,请说明理由.
设复数\(z=\lg (m^{2}-2m-2)+(m^{2}+3m+2)i\),当\(m\)为何值时,
\((1)z\)是实数?
\((2)z\)是纯虚数?
已知复数\(z\)满足\(z+2i\)和\(\dfrac{z}{2-{i}}(i\)为虚数单位\()\)均为实数.
\((2)\)若\(|z+mi|\leqslant 5\),求实数\(m\)的取值范围.
已知\(z\)、\(ω\)为复数,\((1+3i)z\)为纯虚数,\(\omega =\dfrac{z}{{2}+{i}}\)且\(|\omega |=5\sqrt{2}\),求复数\(ω\).
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