Cho số phức <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-1"><span class="MJXp-mstyle" id="MJXp-Span-2"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-3">z</span><span class="MJXp-mo" id="MJXp-Span-4" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-mn" id="MJXp-Span-5">2</span><span class="MJXp-mo" id="MJXp-Span-6" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mn" id="MJXp-Span-7">4</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-8">i</span></span></span></span><span id="MathJax-Element-1-Frame" class="mjx-chtml MathJax_CHTML MJXc-processed" tabindex="0" style="font-size: 127%;"><span id="MJXc-Node-1" class="mjx-math"><span id="MJXc-Node-2" class="mjx-mrow"><span id="MJXc-Node-3" class="mjx-mstyle"><span id="MJXc-Node-4" class="mjx-mrow" style="font-size: 144%;"><span id="MJXc-Node-5" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em; padding-right: 0.003em;">z</span></span><span id="MJXc-Node-6" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.101em; padding-bottom: 0.298em;">=</span></span><span id="MJXc-Node-7" class="mjx-mn MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">2</span></span><span id="MJXc-Node-8" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.298em; padding-bottom: 0.445em;">+</span></span><span id="MJXc-Node-9" class="mjx-mn MJXc-space2"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">4</span></span><span id="MJXc-Node-10" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.445em; padding-bottom: 0.298em;">i</span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large z=2+4i</script>. Tìm số phức <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-9"><span class="MJXp-mstyle" id="MJXp-Span-10"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-11">w</span><span class="MJXp-mo" id="MJXp-Span-12" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-13">i</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-14">z</span><span class="MJXp-mo" id="MJXp-Span-15" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-munderover" id="MJXp-Span-16"><span><span class="MJXp-over"><span class=" MJXp-script"><span class="MJXp-mo" id="MJXp-Span-18" style="margin-right: 0px; margin-left: 0px;">¯</span></span><span class=""><span class="MJXp-mi MJXp-italic" id="MJXp-Span-17">z</span></span></span></span></span></span></span></span><span id="MathJax-Element-2-Frame" class="mjx-chtml MathJax_CHTML MJXc-processed" tabindex="0" style="font-size: 127%;"><span id="MJXc-Node-11" class="mjx-math"><span id="MJXc-Node-12" class="mjx-mrow"><span id="MJXc-Node-13" class="mjx-mstyle"><span id="MJXc-Node-14" class="mjx-mrow" style="font-size: 144%;"><span id="MJXc-Node-15" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">w</span></span><span id="MJXc-Node-16" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.101em; padding-bottom: 0.298em;">=</span></span><span id="MJXc-Node-17" class="mjx-mi MJXc-space3"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.445em; padding-bottom: 0.298em;">i</span></span><span id="MJXc-Node-18" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em; padding-right: 0.003em;">z</span></span><span id="MJXc-Node-19" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.298em; padding-bottom: 0.445em;">+</span></span><span id="MJXc-Node-20" class="mjx-munderover MJXc-space2"><span class="mjx-stack"><span class="mjx-over" style="font-size: 70.7%; height: 0.096em; padding-bottom: 0.283em; padding-top: 0.141em; padding-left: 0.038em;"><span id="MJXc-Node-22" class="mjx-mo" style="vertical-align: top;"><span class="mjx-delim-h"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.301em; padding-bottom: 0.833em; margin: 0px -0.07em 0px -0.069em;">¯</span><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.301em; padding-bottom: 0.833em; margin: 0px 0.141em 0px -0.28em; letter-spacing: -0.46em;">¯</span><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.301em; padding-bottom: 0.833em; margin-right: -0.07em; margin-bottom: 0px; margin-top: 0px;">¯</span></span></span></span><span class="mjx-op"><span id="MJXc-Node-21" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em; padding-right: 0.003em;">z</span></span></span></span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-2">\Large w=iz+\overline{z}</script>. $

Cho số phức z=2+4iz=2+4i. Tìm số phức w=iz+¯zw=iz+¯¯¯z. $

Bài sau

4.1/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

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Câu hỏi:

Cho số phức z=2+4iz=2+4i. Tìm số phức w=iz+¯zw=iz+¯¯¯z.

Đáp án án đúng là: A

Lời giải chi tiết:

Chọn A

Ta có: z=2+4iz=2+4i ⇒¯z=2−4i⇒¯¯¯z=2−4i.

Khi đó: w=iz+¯z=i(2+4i)+2−4i=2i+4i2+2−4i=−2−2iw=iz+¯¯¯z=i(2+4i)+2−4i=2i+4i2+2−4i=−2−2i.

Bài sau

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