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The determinant |(cos C,tan A,0),(sin B,...

The determinant `|(cos C,tan A,0),(sin B,0,-tan A),(0,sin B,cos C)|`
has the value, where A, B, C are angled of a triangle

A

0

B

1

C

`sin A sin B`

D

`cos A cos B cos C`

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The correct Answer is:
To find the value of the determinant \[ D = \begin{vmatrix} \cos C & \tan A & 0 \\ \sin B & 0 & -\tan A \\ 0 & \sin B & \cos C \end{vmatrix} \] we can use the property of determinants that allows us to expand along a row or column. In this case, we will expand along the first row. ### Step 1: Expand the determinant Using the first row for expansion, we have: \[ D = \cos C \cdot \begin{vmatrix} 0 & -\tan A \\ \sin B & \cos C \end{vmatrix} - \tan A \cdot \begin{vmatrix} \sin B & -\tan A \\ 0 & \cos C \end{vmatrix} + 0 \cdot \begin{vmatrix} \sin B & 0 \\ 0 & \sin B \end{vmatrix} \] The last term is zero, so we can ignore it. ### Step 2: Calculate the first 2x2 determinant Now we calculate the first 2x2 determinant: \[ \begin{vmatrix} 0 & -\tan A \\ \sin B & \cos C \end{vmatrix} = (0 \cdot \cos C) - (-\tan A \cdot \sin B) = \tan A \sin B \] ### Step 3: Calculate the second 2x2 determinant Next, we calculate the second 2x2 determinant: \[ \begin{vmatrix} \sin B & -\tan A \\ 0 & \cos C \end{vmatrix} = (\sin B \cdot \cos C) - (0 \cdot -\tan A) = \sin B \cos C \] ### Step 4: Substitute back into the determinant Substituting these results back into our expression for \(D\): \[ D = \cos C \cdot (\tan A \sin B) - \tan A \cdot (\sin B \cos C) \] ### Step 5: Simplify the expression Now, we simplify: \[ D = \cos C \tan A \sin B - \tan A \sin B \cos C \] Notice that both terms are identical but with opposite signs, thus: \[ D = 0 \] ### Final Result Therefore, the value of the determinant is: \[ \boxed{0} \]
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OBJECTIVE RD SHARMA ENGLISH-DETERMINANTS-Exercise
  1. If [ ] denotes the greatest integer less than or equal to the real num...

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  2. The coefficicent of x in f(x) =|{:(x,1+sinx,cosx),(1, log(1+x),2),(x^2...

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  3. The determinant |(cos C,tan A,0),(sin B,0,-tan A),(0,sin B,cos C)| h...

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  4. Using the factor theorem it is found that a+b , b+ca n dc+a are three ...

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  5. The value of |(a,a^(2) - bc,1),(b,b^(2) - ca,1),(c,c^(2) - ab,1)|, is

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  6. Find the number of real root of the equation |0x-a x-b x+a0x-c x+b x+c...

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  7. The repeated factor of the determinant |(y +z,x,y),(z +x,z,x),(x +y,...

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  8. The value of the determinant Delta = |((1 - a(1)^(3) b(1)^(3))/(1 - ...

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  9. The determinant Delta = |(b,c,b alpha +c),(c,d,c alpha + d),(b alpha...

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  10. Delta = |(1//a,1,bc),(1//b,1,ca),(1//c,1,ab)|=

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  11. If |(1 +ax,1 +bx,1 + bx),(1 +a(1) x,1 +b(1) x,1 + c(1) x),(1 + a(2) x,...

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  12. If abc!=0 then |{:(1+a,1,1),(1,1+b,1),(1,1,1+c):}| is

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  13. If 1 + (1)/(a) + (1)/(b) + (1)/(c) = 0, then Delta = |(1 +a,1,1),(1,...

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  14. If a, b and c are all different from zero and Delta = |(1 +a,1,1),(1...

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  15. In a Delta ABC, a, b, c are sides and A, B, C are angles opposite to t...

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  16. If |(-12,0,lamda),(0,2,-1),(2,1,15)| = -360, then the value of lamda i...

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  17. If a(i), i=1,2,…..,9 are perfect odd squares, then |{:(a(1),a(2),a(3))...

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  18. If maximum and minimum values of the determinant |{:(1+sin^(2)x,cos...

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  19. If [x] denote the greatest integer less than or equal to x then in ord...

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  20. If a, b gt 0 and Delta (x)= |(x,a,a),(b,x,a),(b,b,x)|, then

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