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The equation Z^(3)+iZ-1=0 has...

The equation `Z^(3)+iZ-1=0` has

A

three real roots

B

one real roots

C

no real roots

D

no real or complex roots

Text Solution

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The correct Answer is:
To solve the equation \( Z^3 + iZ - 1 = 0 \) and determine the nature of its roots, we will follow these steps: ### Step 1: Substitute \( Z \) with \( x \) We start by rewriting the equation: \[ x^3 + ix - 1 = 0 \] ### Step 2: Analyze the equation We can separate the real and imaginary parts of the equation. The real part is \( x^3 - 1 \) and the imaginary part is \( ix \). For the equation to hold, both parts must equal zero. ### Step 3: Set up the equations From the real part: \[ x^3 - 1 = 0 \] From the imaginary part: \[ ix = 0 \implies x = 0 \] ### Step 4: Solve the real part The equation \( x^3 - 1 = 0 \) can be factored as: \[ x^3 = 1 \] This gives us the roots: \[ x = 1 \] The roots of \( x^3 = 1 \) are \( x = 1, \omega, \omega^2 \) where \( \omega = e^{2\pi i / 3} \) (the complex cube roots of unity). ### Step 5: Check for real roots We already found \( x = 0 \) from the imaginary part. Now we check if \( x = 1 \) satisfies the original equation: \[ 1^3 + i(1) - 1 = 1 + i - 1 = i \neq 0 \] Thus, \( x = 1 \) is not a root. ### Step 6: Conclusion about the roots Since \( x = 0 \) does not satisfy the equation and \( x = 1 \) also does not satisfy it, we conclude that there are no real roots. The complex roots are \( \omega \) and \( \omega^2 \). ### Final Answer The equation \( Z^3 + iZ - 1 = 0 \) has **no real roots**. ---

To solve the equation \( Z^3 + iZ - 1 = 0 \) and determine the nature of its roots, we will follow these steps: ### Step 1: Substitute \( Z \) with \( x \) We start by rewriting the equation: \[ x^3 + ix - 1 = 0 \] ...
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