Math Problem Statement
Let $z$ and $w$ be complex numbers such that $|z| = |w| = 1$ and $zw \ne -1.$
(a) Prove that $\overline{z} = \frac{1}{z}$ and $\overline{w} = \frac{1}{w}.$
Solution
To prove that and , let's break the problem down step by step for . The same reasoning will apply for .
Step 1: Use the property
Given that , recall that the modulus of a complex number , where and are real, is defined as:
However, since , this implies:
This tells us that the complex number lies on the unit circle in the complex plane.
Step 2: Conjugate of
The complex conjugate of is:
Step 3: Inverse of
The inverse of is given by:
To simplify , we multiply both the numerator and the denominator by the complex conjugate of , which is . This yields:
Since we know (from Step 1), the expression simplifies to:
Thus, we have shown that:
Step 4: Apply the same reasoning to
Since , we can follow exactly the same steps as above to show that:
Conclusion
We have proven that:
Would you like further clarification or details on any part?
Here are some related questions:
- How does the unit circle help in understanding complex numbers?
- Can you show a general proof for other moduli ?
- How would this change if and were not on the unit circle?
- What other properties of complex numbers can be derived from ?
- How can this proof be extended to other forms of , such as polar form?
Tip: When dealing with complex numbers on the unit circle, it's often helpful to use their polar form, , where computations involving modulus and conjugates become more straightforward.
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Math Problem Analysis
Mathematical Concepts
Complex Numbers
Conjugate
Inverse
Modulus
Formulas
|z| = \sqrt{a^2 + b^2}
\overline{z} = a - bi
\frac{1}{z} = \frac{a - bi}{a^2 + b^2}
Theorems
Modulus of a complex number
Properties of complex conjugates
Inverse of a complex number on the unit circle
Suitable Grade Level
Undergraduate Mathematics or Advanced High School
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