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Statement-1: for any non-zero complex nu...

Statement-1: for any non-zero complex number `|z-1| le ||z|-1|+|z|` arg (z)
Statement-2 : For any non-zero complex number z
`|z/(|z|)-1| le "arg"(z)`

A

Statement-1 is True, Statement-2 is True: Statement-2 is a correct exp,anation for statement-1.

B

Statement-1 is true, statement -2 is true, Statement-2 is not a correct explanation for statement-1.

C

Statement-1 is True, statement-2 is false,

D

statement-1 is False, Statement-2 is true.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given problem, we need to analyze both statements and show that they are true. Let's break down the solution step by step. ### Step 1: Understanding Statement 2 The second statement is: \[ \left| \frac{z}{|z|} - 1 \right| \leq \arg(z) \] where \( z \) is a non-zero complex number. **Hint for Step 1:** Recall that for any complex number \( z = r(\cos \theta + i \sin \theta) \), where \( r = |z| \) and \( \theta = \arg(z) \). ### Step 2: Expressing \( z \) We can express \( z \) in terms of its modulus and argument: \[ z = r(\cos \theta + i \sin \theta) \] Thus, we have: \[ |z| = r \] and \[ \arg(z) = \theta \] **Hint for Step 2:** Remember that the modulus \( |z| \) is the distance from the origin in the complex plane. ### Step 3: Simplifying the Left-Hand Side of Statement 2 Now, we compute the left-hand side: \[ \frac{z}{|z|} = \frac{r(\cos \theta + i \sin \theta)}{r} = \cos \theta + i \sin \theta \] Thus, \[ \left| \frac{z}{|z|} - 1 \right| = \left| (\cos \theta + i \sin \theta) - 1 \right| = \left| (\cos \theta - 1) + i \sin \theta \right| \] **Hint for Step 3:** Use the formula for the modulus of a complex number: \( |a + bi| = \sqrt{a^2 + b^2} \). ### Step 4: Calculating the Modulus Now we calculate: \[ \left| (\cos \theta - 1) + i \sin \theta \right| = \sqrt{(\cos \theta - 1)^2 + \sin^2 \theta} \] Using the identity \( \sin^2 \theta + \cos^2 \theta = 1 \): \[ = \sqrt{(\cos^2 \theta - 2\cos \theta + 1) + \sin^2 \theta} = \sqrt{2 - 2\cos \theta} = \sqrt{2(1 - \cos \theta)} = \sqrt{2 \cdot 2\sin^2\left(\frac{\theta}{2}\right)} = 2\left|\sin\left(\frac{\theta}{2}\right)\right| \] **Hint for Step 4:** Use the half-angle identity: \( 1 - \cos \theta = 2\sin^2\left(\frac{\theta}{2}\right) \). ### Step 5: Establishing the Inequality Now we need to show: \[ 2\left|\sin\left(\frac{\theta}{2}\right)\right| \leq \theta \] This is true since \( \sin x \leq x \) for \( x \geq 0 \). **Hint for Step 5:** Recall the property of the sine function that \( \sin x \leq x \) for all \( x \geq 0 \). ### Step 6: Conclusion for Statement 2 Thus, we conclude that Statement 2 is true. ### Step 7: Understanding Statement 1 The first statement is: \[ |z - 1| \leq ||z| - 1| + |z| \cdot \arg(z) \] **Hint for Step 7:** Use the triangle inequality to analyze the modulus expressions. ### Step 8: Applying the Triangle Inequality We can rewrite \( z \) as: \[ z = |z|(\cos \theta + i \sin \theta) \] Then, \[ |z - 1| = | |z|(\cos \theta + i \sin \theta) - 1 | \] **Hint for Step 8:** Remember that the triangle inequality states \( |a + b| \leq |a| + |b| \). ### Step 9: Breaking Down the Expression Using the triangle inequality: \[ |z - 1| = ||z|(\cos \theta + i \sin \theta) - 1| \leq ||z| - 1| + |z| \] **Hint for Step 9:** Consider \( |z| \) as a constant and analyze how it interacts with the other terms. ### Step 10: Finalizing Statement 1 Since we have established that both statements are true, we conclude that: - Statement 1 is true. - Statement 2 is true. Thus, both statements are validated. ### Final Answer Both Statement 1 and Statement 2 are true.
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