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R=[(x,0,0),(0,y,0),(0,0,z)],x/sintheta=y...

`R=[(x,0,0),(0,y,0),(0,0,z)],x/sintheta=y/sin(0+(2pi)/3)=z/sin(0+(4pi)/3)`
Statement-1: Trace (R) = 0
Statement-2: Trace (adj(adj(R))=0

A

Statement-1 is true and statement-2 is false

B

Statement-1 is false and statement-2 is false

C

Statement-1 is false and statement-2 is true

D

Statement-1 is true and statement-2 is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step-by-step, we will analyze the given matrix \( R \) and the conditions provided in the question. ### Step 1: Define the Matrix \( R \) The matrix \( R \) is given as: \[ R = \begin{pmatrix} x & 0 & 0 \\ 0 & y & 0 \\ 0 & 0 & z \end{pmatrix} \] ### Step 2: Analyze the Ratios We have the ratios: \[ \frac{x}{\sin \theta} = \frac{y}{\sin\left(0 + \frac{2\pi}{3}\right)} = \frac{z}{\sin\left(0 + \frac{4\pi}{3}\right)} \] Let’s denote this common ratio as \( k \): \[ x = k \sin \theta, \quad y = k \sin\left(\frac{2\pi}{3}\right), \quad z = k \sin\left(\frac{4\pi}{3}\right) \] ### Step 3: Calculate \( y \) and \( z \) From trigonometric values: \[ \sin\left(\frac{2\pi}{3}\right) = \sin\left(180^\circ - 60^\circ\right) = \sin 60^\circ = \frac{\sqrt{3}}{2} \] \[ \sin\left(\frac{4\pi}{3}\right) = \sin\left(180^\circ + 60^\circ\right) = -\sin 60^\circ = -\frac{\sqrt{3}}{2} \] Thus, we can express \( y \) and \( z \) as: \[ y = k \cdot \frac{\sqrt{3}}{2}, \quad z = k \cdot \left(-\frac{\sqrt{3}}{2}\right) \] ### Step 4: Calculate \( x + y + z \) Now, we can find \( x + y + z \): \[ x + y + z = k \sin \theta + k \cdot \frac{\sqrt{3}}{2} - k \cdot \frac{\sqrt{3}}{2} = k \sin \theta \] This implies: \[ x + y + z = k \sin \theta \] ### Step 5: Determine the Trace of \( R \) The trace of matrix \( R \) is given by: \[ \text{Trace}(R) = x + y + z = k \sin \theta \] To satisfy Statement 1, we need \( \text{Trace}(R) = 0 \). This occurs if: \[ k \sin \theta = 0 \] Thus, either \( k = 0 \) or \( \sin \theta = 0 \). ### Step 6: Calculate the Adjoint of \( R \) The adjoint of \( R \) is given by: \[ \text{adj}(R) = \begin{pmatrix} yz & 0 & 0 \\ 0 & xz & 0 \\ 0 & 0 & xy \end{pmatrix} \] ### Step 7: Calculate the Adjoint of the Adjoint Now we need to find \( \text{adj}(\text{adj}(R)) \): \[ \text{adj}(\text{adj}(R)) = \begin{pmatrix} 0 & 0 & 0 \\ 0 & 0 & 0 \\ 0 & 0 & xyz \end{pmatrix} \] The trace of this matrix is \( 0 \) if \( x + y + z = 0 \). ### Conclusion Both statements are correct: - Statement 1: \( \text{Trace}(R) = 0 \) - Statement 2: \( \text{Trace}(\text{adj}(\text{adj}(R))) = 0 \)
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