Giả sử ta có hệ thức <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-msubsup" id="MJXp-Span-3"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-4" style="margin-right: 0.05em;">a</span><span class="MJXp-mn MJXp-script" id="MJXp-Span-5" style="vertical-align: 0.5em;">2</span></span><span class="MJXp-mo" id="MJXp-Span-6" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-msubsup" id="MJXp-Span-7"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-8" style="margin-right: 0.05em;">b</span><span class="MJXp-mn MJXp-script" id="MJXp-Span-9" style="vertical-align: 0.5em;">2</span></span><span class="MJXp-mo" id="MJXp-Span-10" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-mn" id="MJXp-Span-11">7</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-12">a</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-13">b</span><span class="MJXp-mo" id="MJXp-Span-14" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-15">a</span><span class="MJXp-mo" id="MJXp-Span-16" style="margin-left: 0em; margin-right: 0.222em;">,</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-17">b</span><span class="MJXp-mo" id="MJXp-Span-18" style="margin-left: 0.333em; margin-right: 0.333em;">></span><span class="MJXp-mn" id="MJXp-Span-19">0</span><span class="MJXp-mo" id="MJXp-Span-20" style="margin-left: 0em; margin-right: 0em;">)</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-msubsup"><span class="mjx-base"><span id="MJXc-Node-6" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">a</span></span></span><span class="mjx-sup" style="font-size: 70.7%; vertical-align: 0.513em; padding-left: 0px; padding-right: 0.071em;"><span id="MJXc-Node-7" class="mjx-mn" style=""><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">2</span></span></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-msubsup MJXc-space2"><span class="mjx-base"><span id="MJXc-Node-10" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.495em; padding-bottom: 0.298em;">b</span></span></span><span class="mjx-sup" style="font-size: 70.7%; vertical-align: 0.513em; padding-left: 0px; padding-right: 0.071em;"><span id="MJXc-Node-11" class="mjx-mn" style=""><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">2</span></span></span></span><span id="MJXc-Node-12" 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-13" class="mjx-mn MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">7</span></span><span id="MJXc-Node-14" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">a</span></span><span id="MJXc-Node-15" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.495em; padding-bottom: 0.298em;">b</span></span><span id="MJXc-Node-16" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.445em; padding-bottom: 0.593em;">(</span></span><span id="MJXc-Node-17" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">a</span></span><span id="MJXc-Node-18" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="margin-top: -0.145em; padding-bottom: 0.544em;">,</span></span><span id="MJXc-Node-19" class="mjx-mi MJXc-space1"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.495em; padding-bottom: 0.298em;">b</span></span><span id="MJXc-Node-20" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.249em; padding-bottom: 0.396em;">></span></span><span id="MJXc-Node-21" class="mjx-mn MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">0</span></span><span id="MJXc-Node-22" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.445em; padding-bottom: 0.593em;">)</span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large a^2+b^2=7ab (a, b>0)</script>. Hệ thức nào sau đâ

Giả sử ta có hệ thức a2+b2=7ab(a,b>0)a2+b2=7ab(a,b>0). Hệ thức nào sau đâ

4.3/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

Lưu về Facebook:

Câu hỏi:

Giả sử ta có hệ thức a2+b2=7ab(a,b>0)a2+b2=7ab(a,b>0). Hệ thức nào sau đây là đúng?

Đáp án án đúng là: D

Lời giải chi tiết:

Chọn D

Ta có:

a2+b2=7ab(a+b)2=9ablog2(a+b)2=log2(9ab)log2(a+b3)2=log2(ab)2log2(a+b3)=log2a+log2b