Xét <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">I</span><span class="MJXp-mo" id="MJXp-Span-4" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-msubsup" id="MJXp-Span-5"><span class="MJXp-mo" id="MJXp-Span-6" style="margin-left: 0em; margin-right: 0.05em;">∫</span><span class="MJXp-script-box" style="height: 2.004em; vertical-align: -0.64em;"><span class=" MJXp-script"><span><span style="margin-bottom: -0.25em;"><span class="MJXp-mrow" id="MJXp-Span-9"><span class="MJXp-msqrt" id="MJXp-Span-10"><span class="MJXp-surd"><span style="font-size: 134%; margin-top: 0.104em;">√</span></span><span class="MJXp-root"><span class="MJXp-rule" style="border-top: 0.08em solid;"></span><span class="MJXp-box"><span class="MJXp-mn" id="MJXp-Span-11">3</span></span></span></span></span></span></span></span><span class=" MJXp-script"><span><span style="margin-top: -1.03em;"><span class="MJXp-mrow" id="MJXp-Span-7"><span class="MJXp-mn" id="MJXp-Span-8">0</span></span></span></span></span></span></span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-12">x</span><span class="MJXp-mo" id="MJXp-Span-13" style="margin-left: 0em; margin-right: 0.222em;">.</span><span class="MJXp-msubsup" id="MJXp-Span-14"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-15" style="margin-right: 0.05em;">e</span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-16" style="vertical-align: 0.5em;"><span class="MJXp-msqrt" id="MJXp-Span-17"><span class="MJXp-surd"><span class="MJXp-right MJXp-scale10" style="font-size: 166%; margin-top: 0.084em; margin-left: 0em;">√</span></span><span class="MJXp-root"><span class="MJXp-rule" style="border-top: 0.08em solid;"></span><span class="MJXp-box"><span class="MJXp-msubsup" id="MJXp-Span-18"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-19" style="margin-right: 0.05em;">x</span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-20" style="vertical-align: 0.5em;"><span class="MJXp-mn" id="MJXp-Span-21">2</span></span></span><span class="MJXp-mo" id="MJXp-Span-22">+</span><span class="MJXp-mn" id="MJXp-Span-23">1</span></span></span></span></span></span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-24">d</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-25">x</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: 0.445em; padding-bottom: 0.298em; padding-right: 0.064em;">I</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-msubsup MJXc-space3"><span class="mjx-base" style="margin-right: -0.138em;"><span id="MJXc-Node-8" class="mjx-mo" style="padding-right: 0.138em;"><span class="mjx-char MJXc-TeX-size1-R" style="padding-top: 0.593em; padding-bottom: 0.593em;">∫</span></span></span><span class="mjx-stack" style="vertical-align: -0.366em;"><span class="mjx-sup" style="font-size: 70.7%; padding-bottom: 0.434em; padding-left: 0.324em; 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-msqrt"><span class="mjx-box" style="padding-top: 0.045em;"><span class="mjx-surd"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.495em; padding-bottom: 0.544em;">√</span></span><span class="mjx-box" style="padding-top: 0.119em; border-top: 1.6px solid;"><span id="MJXc-Node-15" class="mjx-mrow"><span id="MJXc-Node-16" 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></span></span></span></span></span><span class="mjx-sub" style="font-size: 70.7%; padding-right: 0.071em;"><span id="MJXc-Node-9" class="mjx-texatom" style=""><span id="MJXc-Node-10" class="mjx-mrow"><span id="MJXc-Node-11" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">0</span></span></span></span></span></span></span><span id="MJXc-Node-17" class="mjx-mi MJXc-space1"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">x</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: 0.347em;">.</span></span><span id="MJXc-Node-19" class="mjx-msubsup MJXc-space1"><span class="mjx-base"><span id="MJXc-Node-20" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">e</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-21" class="mjx-texatom" style=""><span id="MJXc-Node-22" class="mjx-mrow"><span id="MJXc-Node-23" class="mjx-msqrt"><span class="mjx-box" style="padding-top: 0.045em;"><span class="mjx-surd"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.495em; padding-bottom: 0.544em;">√</span></span><span class="mjx-box" style="padding-top: 0.045em; border-top: 1.6px solid;"><span id="MJXc-Node-24" class="mjx-mrow"><span id="MJXc-Node-25" class="mjx-msubsup"><span class="mjx-base"><span id="MJXc-Node-26" 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-sup" style="font-size: 70.7%; vertical-align: 0.409em; 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-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 id="MJXc-Node-30" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.298em; padding-bottom: 0.445em;">+</span></span><span id="MJXc-Node-31" 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 id="MJXc-Node-32" class="mjx-mi"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.495em; padding-bottom: 0.298em; padding-right: 0.003em;">d</span></span><span id="MJXc-Node-33" 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></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large I = \int_{0}^{\sqrt{3}} x.e^{\sqrt{x^{2}+1}} dx</script>. Nếu đặt

Xét I=30x.ex2+1dxI=30x.ex2+1dx. Nếu đặt

4.2/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

Lưu về Facebook:

Câu hỏi:

Xét I=30x.ex2+1dxI=30x.ex2+1dx. Nếu đặt t=x2+1t=x2+1 thì II bằng

Đáp án án đúng là: C

Lời giải chi tiết:

Đặt t=x2+1t=x2+1. Khi đó t2=x2+1t2=x2+1, suy ra 2t dt=2x dx2t dt=2x dx hay xdx=tdtxdx=tdt

Với x = 0 thì t = 1; với x=3x=3 thì t = 2

Do đó, I=21tetdtI=21tetdt