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|(sin alpha, cosalpha,sin(alpha+delta)),...

`|(sin alpha, cosalpha,sin(alpha+delta)),(sinbeta, cos beta,sin(beta+delta)),(singamma,cosgamma,sin(gamma+delta))|=`

A

0

B

1

C

`1+sin alpha sin beta sin gamma`

D

`1-(sin alpha-sin beta)(sin beta-sin gamma)(sin gamma-sinalpha)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the determinant given by \[ D = \begin{vmatrix} \sin \alpha & \cos \alpha & \sin(\alpha + \delta) \\ \sin \beta & \cos \beta & \sin(\beta + \delta) \\ \sin \gamma & \cos \gamma & \sin(\gamma + \delta) \end{vmatrix} \] we will follow these steps: ### Step 1: Expand the determinant using the sine addition formula The sine addition formula states that \[ \sin(A + B) = \sin A \cos B + \cos A \sin B. \] Using this formula, we can express \(\sin(\alpha + \delta)\), \(\sin(\beta + \delta)\), and \(\sin(\gamma + \delta)\): \[ \sin(\alpha + \delta) = \sin \alpha \cos \delta + \cos \alpha \sin \delta, \] \[ \sin(\beta + \delta) = \sin \beta \cos \delta + \cos \beta \sin \delta, \] \[ \sin(\gamma + \delta) = \sin \gamma \cos \delta + \cos \gamma \sin \delta. \] ### Step 2: Substitute these expressions into the determinant Now we can substitute these expressions into the determinant: \[ D = \begin{vmatrix} \sin \alpha & \cos \alpha & \sin \alpha \cos \delta + \cos \alpha \sin \delta \\ \sin \beta & \cos \beta & \sin \beta \cos \delta + \cos \beta \sin \delta \\ \sin \gamma & \cos \gamma & \sin \gamma \cos \delta + \cos \gamma \sin \delta \end{vmatrix} \] ### Step 3: Apply column operations We can simplify the determinant by performing column operations. Let's replace the third column \(C_3\) with \(C_3 - \sin \delta C_2 - \cos \delta C_1\): \[ D = \begin{vmatrix} \sin \alpha & \cos \alpha & 0 \\ \sin \beta & \cos \beta & 0 \\ \sin \gamma & \cos \gamma & 0 \end{vmatrix} \] ### Step 4: Evaluate the determinant Now we can see that the third column consists entirely of zeros. According to the properties of determinants, if any row or column is entirely zero, the value of the determinant is zero. Thus, we conclude that: \[ D = 0. \] ### Final Answer The value of the determinant is \[ \boxed{0}. \]
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