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If the vectors vec a and vec bare linear...

If the vectors `vec a` and `vec b`are linearly independent and satisfying `(sqrt3tantheta+1)vec a + (sqrt3sectheta-2)vec b=vec 0`,then the most general values of `theta` are:

A

`npi - (pi)/(6), n in Z`

B

`2n pi pm (11pi)/(6), n in Z`

C

`n pi pm (pi)/(6), n in Z`

D

`2 npi + (11pi)/(6), n in Z`

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The correct Answer is:
To solve the problem, we start with the given equation involving the vectors \(\vec{a}\) and \(\vec{b}\): \[ (\sqrt{3} \tan \theta + 1) \vec{a} + (\sqrt{3} \sec \theta - 2) \vec{b} = \vec{0} \] Since \(\vec{a}\) and \(\vec{b}\) are linearly independent, the only way for this linear combination to equal the zero vector is if both coefficients are zero. Therefore, we can set up the following equations: 1. \(\sqrt{3} \tan \theta + 1 = 0\) 2. \(\sqrt{3} \sec \theta - 2 = 0\) ### Step 1: Solve the first equation From the first equation: \[ \sqrt{3} \tan \theta + 1 = 0 \] Rearranging gives: \[ \sqrt{3} \tan \theta = -1 \] Thus: \[ \tan \theta = -\frac{1}{\sqrt{3}} \] ### Step 2: Find the angles for \(\tan \theta = -\frac{1}{\sqrt{3}}\) The tangent function is negative in the second and fourth quadrants. The reference angle where \(\tan \theta = \frac{1}{\sqrt{3}}\) is \(\frac{\pi}{6}\). Therefore, the angles where \(\tan \theta = -\frac{1}{\sqrt{3}}\) are: \[ \theta = \pi - \frac{\pi}{6} = \frac{5\pi}{6} \quad \text{(second quadrant)} \] \[ \theta = 2\pi - \frac{\pi}{6} = \frac{11\pi}{6} \quad \text{(fourth quadrant)} \] ### Step 3: Solve the second equation Now, we solve the second equation: \[ \sqrt{3} \sec \theta - 2 = 0 \] Rearranging gives: \[ \sqrt{3} \sec \theta = 2 \] Thus: \[ \sec \theta = \frac{2}{\sqrt{3}} \] ### Step 4: Find the angles for \(\sec \theta = \frac{2}{\sqrt{3}}\) The secant function is positive in the first and fourth quadrants. The corresponding cosine value is: \[ \cos \theta = \frac{\sqrt{3}}{2} \] The angles where \(\cos \theta = \frac{\sqrt{3}}{2}\) are: \[ \theta = \frac{\pi}{6} \quad \text{(first quadrant)} \] \[ \theta = \frac{11\pi}{6} \quad \text{(fourth quadrant)} \] ### Step 5: Combine the results Now we have the angles from both equations: From \(\tan \theta = -\frac{1}{\sqrt{3}}\): - \(\theta = \frac{5\pi}{6} + n\pi\) for \(n \in \mathbb{Z}\) From \(\sec \theta = \frac{2}{\sqrt{3}}\): - \(\theta = \frac{\pi}{6} + 2k\pi\) or \(\theta = \frac{11\pi}{6} + 2k\pi\) for \(k \in \mathbb{Z}\) The most general solutions for \(\theta\) that satisfy both conditions are: \[ \theta = \frac{5\pi}{6} + n\pi \quad \text{and} \quad \theta = \frac{11\pi}{6} + 2k\pi \] ### Final Answer The most general values of \(\theta\) are: \[ \theta = \frac{5\pi}{6} + n\pi \quad \text{and} \quad \theta = \frac{11\pi}{6} + 2k\pi \]

To solve the problem, we start with the given equation involving the vectors \(\vec{a}\) and \(\vec{b}\): \[ (\sqrt{3} \tan \theta + 1) \vec{a} + (\sqrt{3} \sec \theta - 2) \vec{b} = \vec{0} \] Since \(\vec{a}\) and \(\vec{b}\) are linearly independent, the only way for this linear combination to equal the zero vector is if both coefficients are zero. Therefore, we can set up the following equations: ...
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