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The value of (sin frac(pi)(8) + i cos fr...

The value of `(sin frac(pi)(8) + i cos frac(pi)(8))^(8)/((sin frac(pi)(8) - i cos frac(pi)(8))^(8))` is :

A

`-1`

B

0

C

1

D

`2i`

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AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the expression: \[ \frac{(\sin \frac{\pi}{8} + i \cos \frac{\pi}{8})^8}{(\sin \frac{\pi}{8} - i \cos \frac{\pi}{8})^8} \] ### Step 1: Rewrite the expression We can rewrite the numerator and denominator using the property of complex numbers: \[ \sin \frac{\pi}{8} + i \cos \frac{\pi}{8} = i \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right) \] Thus, we can express the numerator as: \[ (\sin \frac{\pi}{8} + i \cos \frac{\pi}{8})^8 = \left( i \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right) \right)^8 \] ### Step 2: Factor out \(i^8\) Now, we can factor out \(i^8\) from the expression: \[ = i^8 \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right)^8 \] Since \(i^8 = 1\), we have: \[ = \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right)^8 \] ### Step 3: Rewrite the denominator Similarly, we can rewrite the denominator: \[ (\sin \frac{\pi}{8} - i \cos \frac{\pi}{8})^8 = \left( -i \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right) \right)^8 \] Factoring out \((-i)^8\): \[ = (-i)^8 \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right)^8 \] Since \((-i)^8 = 1\), we have: \[ = \left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right)^8 \] ### Step 4: Combine the results Now, substituting back into our original expression, we get: \[ \frac{(\sin \frac{\pi}{8} + i \cos \frac{\pi}{8})^8}{(\sin \frac{\pi}{8} - i \cos \frac{\pi}{8})^8} = \frac{\left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right)^8}{\left( \cos \frac{\pi}{8} - i \sin \frac{\pi}{8} \right)^8} = 1 \] ### Conclusion Thus, the value of the given expression is: \[ \boxed{1} \]
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