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Show that 1x32x for all positive real numbers x. Describe when we have equality.

 

Hi! Please provide a full solution.

 

Thanks!

 Oct 24, 2018
 #1
avatar+998 
+13

1x32x1+2xx3xx0(x1)2(x+12)x0

 

We can cancel off the (x1)2, and the x on the bottom, since x must be positive, and squares are always positive.

 

This leaves us with x+120 which is true for all positive x

 

Hence this inequality also applies for all positive x.

 

Equality will apply when x=1, since x+12 is strictly positive, and 1x is strictly positive for x0.

 

Source: 

1) https://math.stackexchange.com/questions/1929829/show-that-frac-1x-ge-3-2-sqrtx-for-all-positive-real-numbers-x-descri

2) https://math.stackexchange.com/questions/1929829/show-that-frac-1x-ge-3-2-sqrtx-for-all-positive-real-numbers-x-descri/1929838

 

If it is urgent, this is all I have. If you need something more detailed, I'm sure someone will be able to better assist you soon. 

 

coolcool

 Oct 24, 2018
 #2
avatar+39 
0

Alright, i was hoping for something a little more detailed, but thanks for trying to help!

FencingKat  Oct 25, 2018

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