Với biểu 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-mo" id="MJXp-Span-3" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mn" id="MJXp-Span-4">2</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-5">a</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">1</span><span class="MJXp-msubsup" id="MJXp-Span-8"><span class="MJXp-mo" id="MJXp-Span-9" style="margin-left: 0em; margin-right: 0.05em;">)</span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-10" style="vertical-align: 0.5em;"><span class="MJXp-mstyle" id="MJXp-Span-11"><span class="MJXp-mfrac" id="MJXp-Span-12" style="vertical-align: 0.25em;"><span class="MJXp-box"><span class="MJXp-mn" id="MJXp-Span-13">3</span></span><span class="MJXp-box" style="margin-top: -0.9em;"><span class="MJXp-denom"><span><span class="MJXp-rule" style="height: 1em; border-top: none; border-bottom: 1px solid; margin: 0.1em 0px;"></span></span><span><span class="MJXp-box"><span class="MJXp-mn" id="MJXp-Span-14">4</span></span></span></span></span></span></span></span></span><span class="MJXp-mo" id="MJXp-Span-15" style="margin-left: 0.333em; margin-right: 0.333em;">></span><span class="MJXp-mo" id="MJXp-Span-16" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mn" id="MJXp-Span-17">2</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-18">a</span><span class="MJXp-mo" id="MJXp-Span-19" style="margin-left: 0.267em; margin-right: 0.267em;">−</span><span class="MJXp-mn" id="MJXp-Span-20">1</span><span class="MJXp-msubsup" id="MJXp-Span-21"><span class="MJXp-mo" id="MJXp-Span-22" style="margin-left: 0em; margin-right: 0.05em;">)</span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-23" style="vertical-align: 0.5em;"><span class="MJXp-mstyle" id="MJXp-Span-24"><span class="MJXp-mfrac" id="MJXp-Span-25" style="vertical-align: 0.25em;"><span class="MJXp-box"><span class="MJXp-mn" id="MJXp-Span-26">5</span></span><span class="MJXp-box" style="margin-top: -0.9em;"><span class="MJXp-denom"><span><span class="MJXp-rule" style="height: 1em; border-top: none; border-bottom: 1px solid; margin: 0.1em 0px;"></span></span><span><span class="MJXp-box"><span class="MJXp-mn" id="MJXp-Span-27">6</span></span></span></span></span></span></span></span></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-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.445em; padding-bottom: 0.593em;">(</span></span><span id="MJXc-Node-6" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">2</span></span><span id="MJXc-Node-7" 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-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;">1</span></span><span id="MJXc-Node-10" class="mjx-msubsup"><span class="mjx-base"><span id="MJXc-Node-11" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.445em; padding-bottom: 0.593em;">)</span></span></span><span class="mjx-sup" style="font-size: 70.7%; vertical-align: 1.162em; padding-left: 0px; padding-right: 0.071em;"><span id="MJXc-Node-12" class="mjx-texatom" style=""><span id="MJXc-Node-13" class="mjx-mrow"><span id="MJXc-Node-14" class="mjx-mstyle" style="font-size: 141.4%;"><span id="MJXc-Node-15" class="mjx-mrow"><span id="MJXc-Node-16" class="mjx-mfrac"><span class="mjx-box MJXc-stacked" style="width: 0.7em; padding: 0px 0.12em;"><span class="mjx-numerator" style="width: 0.7em; top: -1.367em;"><span id="MJXc-Node-17" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">3</span></span></span><span class="mjx-denominator" style="width: 0.7em; bottom: -0.711em;"><span id="MJXc-Node-18" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">4</span></span></span><span class="mjx-line" style="border-bottom: 1.8px solid; top: -0.281em; width: 0.7em;"></span></span><span class="mjx-vsize" style="height: 2.077em; vertical-align: -0.711em;"></span></span></span></span></span></span></span></span><span id="MJXc-Node-19" 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-20" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.445em; padding-bottom: 0.593em;">(</span></span><span id="MJXc-Node-21" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">2</span></span><span id="MJXc-Node-22" 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-23" 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-24" class="mjx-mn MJXc-space2"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">1</span></span><span id="MJXc-Node-25" class="mjx-msubsup"><span class="mjx-base"><span id="MJXc-Node-26" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.445em; padding-bottom: 0.593em;">)</span></span></span><span class="mjx-sup" style="font-size: 70.7%; vertical-align: 1.193em; padding-left: 0px; padding-right: 0.071em;"><span id="MJXc-Node-27" class="mjx-texatom" style=""><span id="MJXc-Node-28" class="mjx-mrow"><span id="MJXc-Node-29" class="mjx-mstyle" style="font-size: 141.4%;"><span id="MJXc-Node-30" class="mjx-mrow"><span id="MJXc-Node-31" class="mjx-mfrac"><span class="mjx-box MJXc-stacked" style="width: 0.7em; padding: 0px 0.12em;"><span class="mjx-numerator" style="width: 0.7em; top: -1.368em;"><span id="MJXc-Node-32" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">5</span></span></span><span class="mjx-denominator" style="width: 0.7em; bottom: -0.733em;"><span id="MJXc-Node-33" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">6</span></span></span><span class="mjx-line" style="border-bottom: 1.8px solid; top: -0.281em; width: 0.7em;"></span></span><span class="mjx-vsize" style="height: 2.1em; vertical-align: -0.733em;"></span></span></span></span></span></span></span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large (2a-1)^{\dfrac{3}{4}}>(2a-1)^{\dfrac{5}{6}}</script>. Kh

Với biểu thức (2a1)34>(2a1)56(2a1)34>(2a1)56. Kh

4.7/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

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Câu hỏi:

Với biểu thức (2a1)34>(2a1)56(2a1)34>(2a1)56. Khi đó cơ số a phải thỏa mãn điều kiện 

 

Đáp án án đúng là: C

Lời giải chi tiết:

Chọn C

34<5634<56 nên $\Large 0<2a-1<1\Leftrightarrow \dfrac{1}{2}