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Câu hỏi: Cho số phức $z=\left( 3-2i \right){{\left( 1+i \right)}^{2}}$. Modun $w=iz+2\bar{z}$ ?
A. $2\sqrt{17}.$
B. $17\sqrt{2}$.
C. $-17\sqrt{2}$.
D. $-2\sqrt{17}$.
Ta có: $z=\left( 3-2i \right){{\left( 1+i \right)}^{2}}=4+6i$
$\bar{z}=4-6i$
$w=iz+2\bar{z}=i\left( 4+6i \right)+2.\left( 4-6i \right)=2-8i$
$\left| w \right|=\sqrt{{{2}^{2}}+{{\left( -8 \right)}^{2}}}=2\sqrt{17}$
A. $2\sqrt{17}.$
B. $17\sqrt{2}$.
C. $-17\sqrt{2}$.
D. $-2\sqrt{17}$.
Ta có: $z=\left( 3-2i \right){{\left( 1+i \right)}^{2}}=4+6i$
$\bar{z}=4-6i$
$w=iz+2\bar{z}=i\left( 4+6i \right)+2.\left( 4-6i \right)=2-8i$
$\left| w \right|=\sqrt{{{2}^{2}}+{{\left( -8 \right)}^{2}}}=2\sqrt{17}$
Đáp án A.