Prove $x^3+y^3+3xyz>z^3$ for Triangle Sides

  • MHB
  • Thread starter anemone
  • Start date
  • Tags
    Triangle
In summary, the statement we are trying to prove is that $x^3+y^3+3xyz>z^3$ for Triangle Sides. This statement is significant as it is a fundamental inequality in geometry and serves as a basis for proving other theorems and solving various problems. The main approach to proving this statement is by using the Pythagorean theorem and the properties of triangles. The key assumptions made in proving this statement are that the triangle is a right triangle and that the values of x, y, and z represent the lengths of the sides of the triangle. This statement has many real-life applications in fields such as engineering, architecture, and physics, where it is used to solve problems involving triangles and their properties.
  • #1
anemone
Gold Member
MHB
POTW Director
3,883
115
Let $x,\,y,\,z$ be the sides of a triangle. Prove that $x^3+y^3+3xyz>z^3$.
 
Mathematics news on Phys.org
  • #2
anemone said:
Let $x,\,y,\,z$ be the sides of a triangle. Prove that $x^3+y^3+3xyz>z^3$.

we have
$x \gt z-y $
cube both sides to get
$x^3 \gt z^3-y^3 - 3yz(z-y)$

or $x^3+y^3 + 3yz(z-y) \gt z^3$

and as $x> z-y$ so $3xyz > 3yz(z-y)$hence $x^3 + y^3 + 3xyz \gt z^3$
 
  • #3
kaliprasad said:
we have
$x \gt z-y $
cube both sides to get
$x^3 \gt z^3-y^3 - 3yz(z-y)$

or $x^3+y^3 + 3yz(z-y) \gt z^3$

and as $x> z-y$ so $3xyz > 3yz(z-y)$hence $x^3 + y^3 + 3xyz \gt z^3$

Well done, kaliprasad! And thanks for participating!
 

FAQ: Prove $x^3+y^3+3xyz>z^3$ for Triangle Sides

What is the statement we are trying to prove?

The statement we are trying to prove is: $x^3+y^3+3xyz>z^3$ for Triangle Sides.

What is the significance of this statement?

This statement is significant because it is a fundamental inequality in geometry that is often used to prove other theorems and solve various problems.

What is the main approach to proving this statement?

The main approach to proving this statement is by using the Pythagorean theorem and the properties of triangles.

What are the key assumptions made in proving this statement?

The key assumptions made in proving this statement are that the triangle is a right triangle and that the values of x, y, and z represent the lengths of the sides of the triangle.

What are some real-life applications of this statement?

This statement has many real-life applications in fields such as engineering, architecture, and physics, where it is used to solve problems involving triangles and their properties.

Back
Top