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If
[
1
−
tan
θ
tan
θ
1
]
[
1
tan
θ
−
tan
θ
1
]
−
1
=
[
a
−
b
b
a
]
\begin{bmatrix} 1 & -\tan \theta \\ \tan \theta & 1 \end{bmatrix} \begin{bmatrix} 1 & \tan \theta \\ -\tan \theta & 1 \end{bmatrix}^{-1} = \begin{bmatrix} a & -b \\ b & a \end{bmatrix}
[
1
tan
θ
−
tan
θ
1
]
[
1
−
tan
θ
tan
θ
1
]
−
1
=
[
a
b
−
b
a
]
…
Problem
If
[
1
−
tan
θ
tan
θ
1
]
[
1
tan
θ
−
tan
θ
1
]
−
1
=
[
a
−
b
b
a
]
\begin{bmatrix} 1 & -\tan \theta \\ \tan \theta & 1 \end{bmatrix} \begin{bmatrix} 1 & \tan \theta \\ -\tan \theta & 1 \end{bmatrix}^{-1} = \begin{bmatrix} a & -b \\ b & a \end{bmatrix}
[
1
tan
θ
−
tan
θ
1
]
[
1
−
tan
θ
tan
θ
1
]
−
1
=
[
a
b
−
b
a
]
, then : (a)
a
=
b
=
1
a = b = 1
a
=
b
=
1
(b)
a
=
cos
2
θ
,
b
=
sin
2
θ
a = \cos 2\theta, b = \sin 2\theta
a
=
cos
2
θ
,
b
=
sin
2
θ
(c)
a
=
sin
2
θ
,
b
=
cos
2
θ
a = \sin 2\theta, b = \cos 2\theta
a
=
sin
2
θ
,
b
=
cos
2
θ
(d)
a
=
1
,
b
=
sin
2
θ
a = 1, b = \sin 2\theta
a
=
1
,
b
=
sin
2
θ
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