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If A+B +C =2S, prove that : cos^2 S + co...

If A+B +C =2S, prove that : `cos^2 S + cos^2 (S- A) + cos^2 (S-B)+ cos^2 (S -C) = 2 +2 cos A cos B cos C`.

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MODERN PUBLICATION-TRIGNOMETRY-EXERCISE
  1. If A+B +C +D= 2 pi, prove that : cos A + cos B + cos C + cos D =-4 cos...

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  2. If A+B +C =2S, prove that : sin (S - A) + sin (S- B) + sin (S-C)-sinS=...

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  3. If A+B +C =2S, prove that : cos^2 S + cos^2 (S- A) + cos^2 (S-B)+ cos^...

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  4. If x +y+ z=xyz, prove that : (2x)/(1-x^2)+(2y)/(1-y^2)+(2z)/(1-z^2)= ...

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  5. If x +y+ z=xyz, prove that : (3x-x^3)/(1-3x^2)+ (3y-y^3)/(1-3y^2)+(3z...

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  6. If xy + yz + zx = 1, prove that : x/(1-x^2)+y/(1-y^2)+z/(1-z^2)= (4xy...

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  7. Find the solutions x in [0,2 pi] of : sin 2x-12 (sin x -cos x) + 12 =...

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  8. Solve the following trigonometric equation : cos 3 theta + 8cos^3 th...

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  9. If tan(pi cos theta )= cot (pi sin theta ) ,then cos^(2)(theta -pi/...

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  10. Find all the solution of 4 cos^(2)x sinx -2 sin^(2) x=3 sinx

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  11. In any triangle ABC, prove that : (b^2-c^2)/(a^2)= sin (B -C)/sin(B+C)...

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  12. Find the radian measure of the following degree measure 40°20

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  13. Radian measures of 520^(@) is :

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  14. The value of (25)^0 is :

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  15. Find the value of : sin 765^@.

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  16. Find the value of : tan frac (19 pi)(3).

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  17. Value of sin frac (31 pi)(3) is :

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  18. Let sin theta be -ve and cos theta be + ve, then theta lies in :

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  19. Let sin theta= -1/2 and cos theta= -sqrt3/2, then theta lies in :

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  20. If sin theta=sqrt3/2 and cos theta= -1/2 then theta lies in :

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