Hình bên là đồ thị của ba hàm số <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">y</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-mi MJXp-italic" id="MJXp-Span-6" style="margin-right: 0.05em;">a</span><span class="MJXp-mi MJXp-italic MJXp-script" id="MJXp-Span-7" style="vertical-align: 0.5em;">x</span></span><span class="MJXp-mo" id="MJXp-Span-8" style="margin-left: 0em; margin-right: 0.222em;">;</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-9">y</span><span class="MJXp-mo" id="MJXp-Span-10" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-msubsup" id="MJXp-Span-11"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-12" style="margin-right: 0.05em;">b</span><span class="MJXp-mi MJXp-italic MJXp-script" id="MJXp-Span-13" style="vertical-align: 0.5em;">x</span></span><span class="MJXp-mo" id="MJXp-Span-14" style="margin-left: 0em; margin-right: 0.222em;">;</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-15">y</span><span class="MJXp-mo" id="MJXp-Span-16" style="margin-left: 0.333em; margin-right: 0.333em;">=</span><span class="MJXp-msubsup" id="MJXp-Span-17"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-18" style="margin-right: 0.05em;">c</span><span class="MJXp-mi MJXp-italic MJXp-script" id="MJXp-Span-19" style="vertical-align: 0.5em;">x</span></span><span class="MJXp-mo" id="MJXp-Span-20" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mn" id="MJXp-Span-21">0</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-22">a</span><span class="MJXp-mo" id="MJXp-Span-23" style="margin-left: 0.333em; margin-right: 0.333em;">></span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-24">c</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: 0.495em; padding-right: 0.006em;">y</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"><span id="MJXc-Node-8" 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-9" class="mjx-mi" style=""><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">x</span></span></span></span><span id="MJXc-Node-10" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.15em; padding-bottom: 0.544em;">;</span></span><span id="MJXc-Node-11" class="mjx-mi MJXc-space1"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.495em; padding-right: 0.006em;">y</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-msubsup MJXc-space3"><span class="mjx-base"><span id="MJXc-Node-14" 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-15" class="mjx-mi" style=""><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">x</span></span></span></span><span id="MJXc-Node-16" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.15em; padding-bottom: 0.544em;">;</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: 0.495em; padding-right: 0.006em;">y</span></span><span id="MJXc-Node-18" 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-19" class="mjx-msubsup MJXc-space3"><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;">c</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-mi" style=""><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">x</span></span></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 id="MJXc-Node-23" class="mjx-mn"><span class="mjx-char MJXc-TeX-main-R" style="padding-top: 0.396em; padding-bottom: 0.347em;">0</span></span><span id="MJXc-Node-24" 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-25" 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-26" class="mjx-mi MJXc-space3"><span class="mjx-char MJXc-TeX-math-I" style="padding-top: 0.199em; padding-bottom: 0.298em;">c</span></span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large y=a^x; y=b^x; y=c^x (0 a > c</script>

Hình bên là đồ thị của ba hàm số y=ax;y=bx;y=cx(0a>cy=ax;y=bx;y=cx(0a>c

4.1/5

Tác giả: Thầy Tùng

Đăng ngày: 18 Aug 2022

Lưu về Facebook:
Hình minh họa Hình bên là đồ thị của ba hàm số $\Large y=a^x; y=b^x; y=c^x (0 a > c$

Câu hỏi:

Hình bên là đồ thị của ba hàm số $\Large y=a^x; y=b^x; y=c^x (0

Hình câu hỏi 1. Hình bên là đồ thị của ba hàm số $\Large y=a^x; y=b^x; y=c^x (0 a > c$

 

Đáp án án đúng là: A

Lời giải chi tiết:

Chọn A

Do y=axy=axy=bxy=bx là hai hàm đồng biến nên a,b>1a,b>1

Do y=cxy=cx nghịch biến nên c<1c<1. Vậy cc bé nhất

Mặt khác, lấy x=m>0x=m>0, khi đó tồn tại y1,y2y1,y2 để {am=y1bm=y2

Dễ thấy $\Large y_{1}

Vậy b>a>c