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If alpha=(2pi)/(7) then prove that sin a...

If `alpha=(2pi)/(7)` then prove that `sin alpha sin 2 sin 4 alpha =-(sqrt(7))/(8)`

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If alpha= (2pi)/(7) , then prove that cos alpha+ cos 2 alpha+ cos 4alpha=-(1)/(2) . Hence, deduce that sin alpha+ sin 2alpha+ sin 4alpha=(sqrt(7))/(2)

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CHHAYA PUBLICATION-MISCELLANEOUS EXAMPLES-TRIGONOMETRY
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  2. If a cos theta+ b sin theta= c then find the quadratic equation whose...

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  3. If alpha=(2pi)/(7) then prove that sin alpha sin 2 sin 4 alpha =-(sqrt...

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  4. If A,B,C are the angles of a triangle, show that that greatest value o...

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  5. If A,B,C are the angles of a triangle, find the maximum values of : ...

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  6. If A,B,C are the angles of a triangle, find the maximum values of : ...

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  7. If A,B,C are the angles a triangle, prove that cos A+ cos B+ cos C le ...

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  8. If A,B,C are the angles of a triangle, prove that the maximum value of...

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  9. If theta+ phi= alpha, where 0 lt theta lt (pi)/(2) ,0 lt phi lt (pi)/(...

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  10. If theta+ phi= alpha, where 0 lt theta lt (pi)/(2) ,0 lt phi lt (pi)/(...

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  11. If theta+ phi= alpha, where 0 lt theta lt (pi)/(2) ,0 lt phi lt (pi)/(...

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  12. Show that (1)/(3) lt (sec^(2) theta - tan theta)/( sec^(2) theta+ tan ...

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  13. Find the minimum values of: "tan"^(2)(A)/(2)+ "tan"^(2) (B)/(2)+"ta...

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  14. Find the minimum values of: cot^(2)A+cot^(2)B+ cot ^(2)C where A,...

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  15. Find the minimum values of: 4sinA+3cosA

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  16. Find the minimum values of: "sin" ^(2) (A)/(2)+"sin"^(2)(B)/(2) +"si...

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  17. If A+B+C= pi and "tan" (B+C-A)/(4) "tan" (C+A-B)/(4) *"tan" (A+B-C)/(4...

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  18. Prove that, |{:(6a,a,a),(12b,2b,2b),(9c,c,-2c):}|=0

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  19. If cos alpha+ cos beta= a sin alpha+ sin beta=b, then show that "ta...

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  20. Determine the value of k for which x-1 is a factor of (x^2 +1)+(x+k)do...

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