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Cho hàm số $f(x) = \frac{4^{x}}{4^{x}+2}$ hãy chọn đáp án đúng

- - - - - hàm số mũ

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#1
KaveZS

KaveZS

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A. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) > f(\frac{3}{2015})  + f(\frac{2012}{2015})$

B. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) = f(\frac{3}{2015})  + f(\frac{2012}{2015})$

C. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) < f(\frac{3}{2015})  + f(\frac{2012}{2015})$

D. $2016f(\frac{1}{2017}) + f(\frac{2016}{2017}) = 2015f(\frac{3}{2015}) + 3f(\frac{2012}{2015})$


Edited by KaveZS, 27-11-2016 - 20:28.


#2
leminhnghiatt

leminhnghiatt

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A. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) > f(\frac{3}{2015})  + f(\frac{2012}{2015})$

B. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) = f(\frac{3}{2015})  + f(\frac{2012}{2015})$

C. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) < f(\frac{3}{2015})  + f(\frac{2012}{2015})$

D. $2016f(\frac{1}{2017}) + f(\frac{2016}{2017}) = 2015f(\frac{3}{2015}) + 3f(\frac{2012}{2015})$

B


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#3
leminhnghiatt

leminhnghiatt

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A. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) > f(\frac{3}{2015})  + f(\frac{2012}{2015})$

B. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) = f(\frac{3}{2015})  + f(\frac{2012}{2015})$

C. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) < f(\frac{3}{2015})  + f(\frac{2012}{2015})$

D. $2016f(\frac{1}{2017}) + f(\frac{2016}{2017}) = 2015f(\frac{3}{2015}) + 3f(\frac{2012}{2015})$

 

Xét $f(1-x)+f(x)=\dfrac{4^x}{4^x+2}+\dfrac{4^{1-x}}{4^{1-x}+2}=1$ (thực hiện quy đồng)

Vậy 

B. $f(\frac{1}{2017}) + f(\frac{2016}{2017}) = f(\frac{3}{2015})  + f(\frac{2012}{2015})=1$


 

 

 


Don't care






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