Square both sides inequality help

In summary, when we square both sides of an inequality, we are raising each side to the second power in order to eliminate any negative values and make the inequality easier to solve. This can be done for any inequality, as long as the original inequality is maintained and the same inequality sign is used. The purpose of squaring both sides is to make the inequality easier to solve, but it is important to keep a few rules in mind, such as removing absolute value symbols and being careful with fractions and variables. However, squaring both sides can sometimes change the solution by introducing extraneous solutions, so it is important to check the validity of the solutions obtained after squaring both sides.
  • #1
evagelos
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Homework Statement



Prove: xyzw[tex]\geq x+y+z+w-3[/tex],where [tex]x\geq 1,y\geq 1,z\geq 1,w\geq 1[/tex]

Homework Equations





The Attempt at a Solution



The only thing i could try is to square both sides but then this leads nowhere.

Any ideas??
 
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  • #2


Start with the following inequalities: (Why are they true?)

0 ≤ (xy-1)(zw-1)
0 ≤ (x-1)(y-1)
0 ≤ (z-1)(w-1)​
 
  • #3


thanks!
 

FAQ: Square both sides inequality help

What does it mean to "square both sides" in an inequality?

When we square both sides of an inequality, we are raising each side to the second power. This is done in order to eliminate any negative values and make the inequality easier to solve.

Can you square both sides of any inequality?

Yes, you can square both sides of any inequality as long as the inequality is maintained. This means that if the original inequality had a greater than or less than sign, the new inequality should also have the same sign.

Why do we square both sides of an inequality?

We square both sides of an inequality in order to make it easier to solve. By eliminating any negative values, we can more easily see the relationship between the two sides of the inequality and determine the solution.

Are there any rules or guidelines to follow when squaring both sides of an inequality?

Yes, there are a few rules to keep in mind when squaring both sides of an inequality. First, make sure to maintain the same inequality sign. Also, if there are any absolute value symbols, they should be removed before squaring. Finally, be careful when dealing with fractions or variables, as the rules for squaring those may be slightly different.

Can squaring both sides of an inequality change the solution?

Yes, squaring both sides of an inequality can sometimes change the solution. This is because squaring can introduce extraneous solutions, which are values that satisfy the squared inequality but not the original one. It is important to check the solutions obtained after squaring both sides to ensure they are valid for the original inequality.

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