Gọi <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;">x</span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-5" style="vertical-align: -0.4em;"><span class="MJXp-mn" id="MJXp-Span-6">1</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-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;">x</span></span></span><span class="mjx-sub" style="font-size: 70.7%; vertical-align: -0.212em; padding-right: 0.071em;"><span id="MJXc-Node-7" class="mjx-texatom" style=""><span id="MJXc-Node-8" class="mjx-mrow"><span id="MJXc-Node-9" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">1</span></span></span></span></span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large x_{1}</script>, <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-7"><span class="MJXp-mstyle" id="MJXp-Span-8"><span class="MJXp-msubsup" id="MJXp-Span-9"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-10" style="margin-right: 0.05em;">x</span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-11" style="vertical-align: -0.4em;"><span class="MJXp-mn" id="MJXp-Span-12">2</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-10" class="mjx-math"><span id="MJXc-Node-11" class="mjx-mrow"><span id="MJXc-Node-12" class="mjx-mstyle"><span id="MJXc-Node-13" class="mjx-mrow" style="font-size: 144%;"><span id="MJXc-Node-14" class="mjx-msubsup"><span class="mjx-base"><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;">x</span></span></span><span class="mjx-sub" style="font-size: 70.7%; vertical-align: -0.212em; padding-right: 0.071em;"><span id="MJXc-Node-16" class="mjx-texatom" style=""><span id="MJXc-Node-17" class="mjx-mrow"><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;">2</span></span></span></span></span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-2">\Large x_{2}</script> là hai nghiệm nguyên dương của bất

Gọi x1x1, x2x2 là hai nghiệm nguyên dương của bất

4.1/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

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Câu hỏi:

Gọi x1x1, x2x2 là hai nghiệm nguyên dương của bất phương trình log2(1+x)<2.log2(1+x)<2. Tính giá trị của P=x1+x2.P=x1+x2.

Đáp án án đúng là: D

Lời giải chi tiết:

Chọn D

Ta có: log2(1+x)<2log2(1+x)<2 0<1+x<40<1+x<4 1<x<3.1<x<3.

Suy ra phương trình có hai nghiệm nguyên dương x1=1x1=1, x2=2.x2=2.

Vậy: P=x1+x2=3.P=x1+x2=3.