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For any triangleABC, the value of determ...

For any `triangleABC`, the value of determinant `|[sin^2A,cotA,1],[sin^2B,cotB,1],[sin^2C,cotC,1]|` is:

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Given,`|[sin^2A,cotA,1],[sin^2B,cotB,1],[sin^2C,cotC,1]|`
det along `C_3`
​=`1(sin^2BcotC−sin^2CcotB)−sin^2AcotC+sin^2CcotA+sin^2AcotB−cotAsin^2B`
A triangle meant it can even be an equilateral triangle
⇒A=B=C=60^@
`|[3/4,1/sqrt(3),1],[3/4,1/sqrt(3),1],[3/4,1/sqrt(3),1]|`
=`sqrt(3)/4[[1,1,1],[1,1,1],[1,1,1]]`
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RD SHARMA-DETERMINANTS-Solved Examples And Exercises
  1. Using the properties of determinants, prove that following |(a-b,-c^2,...

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  2. Prove the identities: |[a, b, c],[ a-b,b-c,c-a],[ b+c,c+a, a+b]|=a^3+...

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  3. For any triangleABC, the value of determinant |[sin^2A,cotA,1],[sin^2B...

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  4. Without expanding, show that the value of each of the determinants is ...

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  5. If x , y in R , then the determinant =|(cosx,-sinx,1),(sinx,cosx,1),(...

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  6. The maximum value of Delta=|(1,1,1),(1,1+sintheta,1),(1+costheta,1,1)...

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  7. Prove that: |[-2a, a+b,a+c],[ b+a,-2b,b+c],[c+a, c+b,-2c]|=4(a+b)(b+c...

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  8. Without expanding, show that the value of each of the determinants is ...

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  9. If m is a positive integer and Dr=|2r-1\ ^m Cr1m^2-1 2^m m+1s in^2(...

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  10. Without expanding, show that "Delta"=|(a-x)^2(a-y)^2(a-z)^2(b-x)^2(b-y...

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  11. Let Deltar=|[r , x , (n(n+1))/2] , [2r-1 , y , n^2] , [3r-2 , z , (n(3...

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  12. If Deltar=|[2^(r-1)2 , 3^(r-1) , 4. 5^(r-1)] , [x , y , z] , [2^n-1 , ...

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  13. Find a quadratic polynomial phi(x) whose zeros are the maximum and mi...

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  14. Let f(x)=|secxcosxsec^2x+cotxcos e cxcos^2xcos^2x cos e c^2x1cos^2xcos...

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  15. Show that: |(a, b-c,c+b), (a+c, b, c-a), (a-b,b+a, c)|=(a+b+c)(a^2+b^2...

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  16. If a , b , c are real numbers, prove that |a b c b c a c a b|=-(a+b+c)...

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  17. Solve: |(a+x, a-x, a-x),(a-x, a+x, a-x),(a-x, a-x, a+x)|=0

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  18. Show that: |(3a,-a+b,-a+c),(-b+a,3b,-b+c),(-c+a,-c+b,3c)|=3(a+b+c)(a b...

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  19. If a,b,c are all distinct and |[a,a^3,a^4-1],[b,b^3,b^4-1],[c,c^3,c^4-...

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  20. Solve : |(x-2, 2x-3, 3x-4), (x-4, 2x-9, 3x-16) ,(x-8 ,2x-27,3x-64)|=0

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