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If alpha(1+isqrt3)/(2), then what is the...

If `alpha(1+isqrt3)/(2),` then what is the value of `1+alpha^(8)+alpha^(16)+alpha^(24)+alpha^(32)` ?

A

0

B

1

C

`omega`

D

`-omega^(2)`

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AI Generated Solution

The correct Answer is:
To solve the problem, we start with the given expression for \( \alpha \): \[ \alpha = \frac{1 + i\sqrt{3}}{2} \] ### Step 1: Rewrite \( \alpha \) We can express \( \alpha \) in a different form. Notice that: \[ \alpha = \frac{1}{2} + \frac{i\sqrt{3}}{2} \] This can be recognized as a complex number in polar form. Specifically, it can be expressed in terms of the cube roots of unity. ### Step 2: Identify \( \alpha \) as a cube root of unity The cube roots of unity are \( 1, \omega, \omega^2 \), where \( \omega = e^{2\pi i / 3} = -\frac{1}{2} + i\frac{\sqrt{3}}{2} \) and \( \omega^2 = e^{-2\pi i / 3} = -\frac{1}{2} - i\frac{\sqrt{3}}{2} \). We can see that: \[ \alpha = -\omega^2 \] ### Step 3: Calculate \( 1 + \alpha^8 + \alpha^{16} + \alpha^{24} + \alpha^{32} \) Now, we need to evaluate: \[ 1 + \alpha^8 + \alpha^{16} + \alpha^{24} + \alpha^{32} \] Substituting \( \alpha = -\omega^2 \): \[ 1 + (-\omega^2)^8 + (-\omega^2)^{16} + (-\omega^2)^{24} + (-\omega^2)^{32} \] ### Step 4: Simplify the powers of \( \alpha \) Calculating the powers: - \( (-\omega^2)^8 = \omega^{16} \) - \( (-\omega^2)^{16} = \omega^{32} \) - \( (-\omega^2)^{24} = \omega^{48} \) - \( (-\omega^2)^{32} = \omega^{64} \) ### Step 5: Reduce the powers modulo 3 Since \( \omega^3 = 1 \), we can reduce the powers modulo 3: - \( \omega^{16} \equiv \omega^{1} \) (since \( 16 \mod 3 = 1 \)) - \( \omega^{32} \equiv \omega^{2} \) (since \( 32 \mod 3 = 2 \)) - \( \omega^{48} \equiv \omega^{0} = 1 \) (since \( 48 \mod 3 = 0 \)) - \( \omega^{64} \equiv \omega^{1} \) (since \( 64 \mod 3 = 1 \)) ### Step 6: Substitute back into the expression Now substituting back, we have: \[ 1 + \omega + \omega^2 + 1 + \omega \] Combine like terms: \[ 2 + 2\omega + \omega^2 \] ### Step 7: Use the property of cube roots of unity We know that: \[ 1 + \omega + \omega^2 = 0 \] Thus, we can replace \( \omega + \omega^2 \) with \(-1\): \[ 2 + 2\omega + \omega^2 = 2 + 2\omega - 1 = 1 + 2\omega \] ### Step 8: Final calculation Since \( 1 + \omega + \omega^2 = 0 \), we have: \[ 1 + 2\omega = 1 - 1 - \omega^2 = -\omega^2 \] ### Final Answer The value of \( 1 + \alpha^8 + \alpha^{16} + \alpha^{24} + \alpha^{32} \) is: \[ -\omega^2 \]

To solve the problem, we start with the given expression for \( \alpha \): \[ \alpha = \frac{1 + i\sqrt{3}}{2} \] ### Step 1: Rewrite \( \alpha \) We can express \( \alpha \) in a different form. Notice that: ...
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