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If A + B + C =180^@, prove that : sin (...

If `A + B + C =180^@`, prove that :
`sin (B + 2C) + sin (C + 2A) + sin (A + 2B) = 4 sin frac (B-C)(2) sin frac (C-A)(2) sin frac (A-B)(2)`.

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MODERN PUBLICATION-TRIGNOMETRY-EXERCISE
  1. If A+B+C=180^(@), then find the value of (cos A)/(sin B sin C)+(cosB)/...

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  2. If A+B+C=pi , then, find sin 2A+ sin 2B+ sin 2C.

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  3. If A + B + C =180^@, prove that : sin (B + 2C) + sin (C + 2A) + sin (...

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  4. If A + B + C =180^@, prove that : sin^2 A+ sin^2 B+sin^2 C=2 (1+cos A...

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  5. If A + B + C =180^@, prove that : sin^2 A+ sin^2 B-sin^2 C=2 sin A sin...

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  6. If A + B + C =180^@, prove that : sin^2 A- sin^2 B+ sin^2 C=2 sin A co...

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  7. If A + B + C =180^@, prove that : cos^2 A+ cos^2 B+cos^2 C=1-2 cos A c...

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  8. If A + B + C =180^@, prove that : cos^2 A+ cos^2 B-cos^2 C= 1-2 sin A ...

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  9. If A + B + C =180^@, prove that : cos^2 A- cos^2 B-cos^2 C=2 cos A sin...

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  10. If A + B + C =180^@, prove that : sin^2 frac (A)(2)+ sin^2 frac (B)(2)...

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  11. If A + B + C =180^@, prove that : sin^2 frac (A)(2)+ sin^2 frac (B)(2)...

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  12. If A + B + C =180^@, prove that : cos^2 frac (A)(2)+ cos^2 frac (B)(2)...

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  13. If A + B + C =pi/2, prove that : cos^2 A +cos^2 B+cos^2 C= 2+2 sin A s...

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  14. If A + B + C =pi/2, prove that : sin^2 A +sin^2 B+sin^2 C= 1-2 sin A s...

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  15. If A + B + C =360^@, prove that : 1-cos^2 A-cos^2 B-cos^2 C+2 cos A co...

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  16. If A + B + C =180^@, prove that : tan A + tan B + tan C = tan A tan B ...

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  17. If A + B + C =180^@, prove that : tan frac (A)(2) tan frac (B)(2)+ tan...

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  18. If A + B + C =180^@, prove that : tan 2A + tan 2B + tan 2C = tan 2A ta...

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  19. If A + B + C =pi/2, prove that : tan A tan B + tan B tanC +tanC tan A=...

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  20. If A + B + C =pi/2, prove that : cot A + cot B + cot C = cot A cot B c...

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