Prove Complex Inequality: $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$

In summary, a complex inequality involves complex numbers written in the form a + bi, and the expression $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)$ represents the product of the sums of the absolute values of two complex numbers and the absolute values of their sum and difference. This inequality is important because it is a generalization of the triangle inequality and has various mathematical applications. It can be proven using the Cauchy-Schwarz inequality and can be extended to any finite number of complex numbers.
  • #1
siddjain
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Prove that $$(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|) >= \sqrt{2}$$
 
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  • #2
Apply the inequality $$|A|+|B|\geq |A+B|$$ for ##A=z_1+z_2, B=z_1-z_2##

Then apply it again for ##A=z_1+z_2,B=z_2-z_1##.

You ll get two inequalities, add them and it should be straightforward to proceed.

EDIT: Well, using the above suggestion I think you can only prove a lower bound of 1 not ##\sqrt{2}##.
 
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  • #3
The given condition says
[tex]z_1=e^{i\phi_1}\cos\theta[/tex]
[tex]z_2=e^{i\phi_2}\sin\theta[/tex]
How about substituting them in the forlmula?
 

FAQ: Prove Complex Inequality: $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$

What is the meaning of the complex inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$?

The complex inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ represents a mathematical relationship between two complex numbers, $z_1$ and $z_2$. It states that the product of the sum of the absolute values of $z_1$ and $z_2$ and the sum of the absolute values of $z_1$ and $z_2$ must be greater than or equal to the square root of 2.

What is the significance of the inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ in mathematics?

The inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ is significant in mathematics because it is a fundamental property of complex numbers. It demonstrates the relationship between the sum and absolute values of two complex numbers and the square root of 2.

How can the complex inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ be proven?

The complex inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ can be proven using the properties of complex numbers and basic algebraic manipulations. By expanding the left side of the inequality and simplifying, it can be shown that the inequality holds true for all possible values of $z_1$ and $z_2$.

What is the role of the inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ in solving complex equations?

The inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ is often used as a tool in solving complex equations. It can be used to simplify and manipulate equations involving complex numbers, making them easier to solve. It can also be used to prove the validity of solutions to complex equations.

What are some real-world applications of the complex inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$?

The complex inequality $(|z_1 + z_2| + |z_1 - z_2|)(|z_1| + |z_2|)>=\sqrt{2}$ has various applications in fields such as engineering, physics, and economics. It can be used to model and analyze complex systems, such as electrical circuits or chemical reactions. It is also used in signal processing and image compression algorithms. In economics, it can be used to study market behavior and optimize resource allocation.

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