A^T A^-1 or A^-1 B for matrices like [1, tan t; -tan t, 1]

1. A.
   $\begin{pmatrix}1&2\sqrt{3}\\2\sqrt{3}&1\end{pmatrix}$
2. B.
   $\begin{pmatrix}-1&-2\sqrt{3}\\2\sqrt{3}&1\end{pmatrix}$
3. C.
   $\begin{pmatrix}0&2\sqrt{3}\\2\sqrt{3}&0\end{pmatrix}$
4. D.
   $\begin{pmatrix}0&-2\sqrt{3}\\2\sqrt{3}&0\end{pmatrix}$

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1. A.
   $\begin{pmatrix}-\cos2x & \sin2x\\ -\sin2x & \cos2x\end{pmatrix}$
2. B.
   $\begin{pmatrix}\cos2x & -\sin2x\\ \sin2x & \cos2x\end{pmatrix}$
3. C.
   $\begin{pmatrix}\cos2x & \sin2x\\ -\sin2x & \cos2x\end{pmatrix}$
4. D.
   $\begin{pmatrix}\cos2x & -\sin2x\\ -\sin2x & \cos2x\end{pmatrix}$

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1. A.
   $\begin{bmatrix} \cos2x & - \sin2x \\ - \sin2x & \cos2x \end{bmatrix}$
2. B.
   $\begin{bmatrix} \cos2x & - \sin2x \\ \sin2x & \cos2x \end{bmatrix}$
3. C.
   $\begin{bmatrix} - \cos2x & \sin2x \\ \sin2x & \cos2x \end{bmatrix}$
4. D.
   $\begin{bmatrix} - \cos2x & \sin2x \\ - \sin2x & \cos2x \end{bmatrix}$

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1. A.
   $\ {\csc}^{2}\frac{\theta}{2}{\text{ }A}^{T}$
2. B.
   $\frac{- \sin^{2}\theta}{2}A^{T}$
3. C.
   $\left( \frac{1 + \cos\theta}{2} \right)A^{T}$
4. D.
   $\left( \frac{1 - \cos\theta}{2} \right)A^{T}$

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1. A.
   $\begin{bmatrix} \cos\theta & \sin\theta \\ -\sin\theta & \cos\theta \end{bmatrix}$
2. B.
   $\begin{bmatrix} \cos\theta & -\sin\theta \\ \sin\theta & \cos\theta \end{bmatrix}$
3. C.
   $\begin{bmatrix} \sin\theta & -\cos\theta \\ \cos\theta & \sin\theta \end{bmatrix}$
4. D.
   $\begin{bmatrix} \cos\theta & \sin\theta \\ \sin\theta & \cos\theta \end{bmatrix}$

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