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IF F(x) is increasing function and limit x→infinity f(3x)/f(x) =1 then limit x→infinity f(2x)/f(x) =?

rohit kumar , 15 Years ago
Grade 12
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Padma Bhushan Borah

since f(x) is increasing, so       f(3x)>f(2x)>f(x) => f(3x)/f(x)>f(2x)/f(x)>1 so  Lt of x->infinity=>f(2x)/f(x)=1 (by sandwich theorem).

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Last Activity: 15 Years ago
SAGAR SINGH - IIT DELHI

Dear rohit,

since f(x) is increasing, so       f(3x)>f(2x)>f(x)

Hence we can say,

f(3x)/f(x)>f(2x)/f(x)>1 so  Lt of x->infinity=>f(2x)/f(x)=1

Here we have used sandwich theorem.

To know more abt the theorem, please refer: http://www.sosmath.com/calculus/limcon/limcon03/limcon03.html

We are all IITians and here to help you in your IIT JEE preparation.

All the best.

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Sagar Singh

B.Tech IIT Delhi

sagarsingh24.iitd@gmail.com

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Last Activity: 15 Years ago
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