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sum a^(3) cos (B-C) =...

` sum a^(3) cos (B-C) ` =

A

` 3abc `

B

` abc `

C

` 2abc `

D

` 0 `

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The correct Answer is:
A
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  8. If 2sqrt3 is the inradius of an equilateral triangle then the leng...

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  9. The inventre of Delta ABC is the of its excentral triangle

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  10. cos ^(2) ((A)/(2)) + cos ^(2) ((B)/(2)) +cos ^(2) (( C )/(2)) =

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  12. If p1 ,p2,p3 are the lengths of altitudes of Delta ABC from the ...

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  13. If P1 , P2 , P3 are lengths of altitudes of a triangle from its v...

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  14. In Delta ABC, if a= 30 ,b= 24, c= 18 , then r=

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  16. If 2,3,6 are exradii of triangle , then its inradius is

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  17. If the area of a triangle is 6.sq units and its inradius is 2 unit...

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  18. If the area of Delta ABC with sides a,b,c is Delta, then the are...

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  19. In Delta ABC, if r2 = 3 , r3 = 4 then the length of the altitude ...

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  20. If r1 = 36,r2 = 18 r3 = 12 then the area of Delta ABC is

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