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In any DeltaABC, 2 [bc cos A + ca cos B+...

In any `DeltaABC, 2 [bc cos A + ca cos B+ ab cos C]=`

A

`a^(2)+ b ^(2)+ c ^(2)`

B

`a ^(2) + b ^(2)-c^(2)`

C

`a ^(2)-b^(2)+c^(2)`

D

`a ^(2) -b^(2)+ c ^(2)`

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ARIHANT MATHS-PROPERTIES AND SOLUTION OF TRIANGLES -Exercise For Sesssion 1
  1. In the given figure,if AB= AC, angle BAD=30^(@)and AE=AD, then x is eq...

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  2. In DeltaABC, a=4, b =12 and B=60^(@), thn the vlaue of sin A is

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  3. Let ABC be a triangle such that angle A =45^(@) , angle B =75^(@), the...

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  4. If the angles A, B, C of DeltaABC are in A.P. and b:c=sqrt(3):sqrt(2),...

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  5. If cot ""A/2 =(b+c)/(a),then DeltaABC is

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  6. In any triangle. if(a^2-b^2)/(a^2+b^2)=("sin"(A-B))/("sin"(A+B)) , the...

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  7. In any triangle A B C , prove that: (a^2sin(B-C))/(sinB+sin C)+(b^2sin...

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  8. In any DeltaABC, is 2 cos B=a/c, then the triangle is

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  9. Prove that sin^2(pi/4) + cos^2(pi/6) - tan^2(pi/4) = 1/4

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  10. If a cos A =b cos B, then the triange is

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  11. In Delta ABC, (a + b+ c) (b + c -a) = kbc if

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  12. If : a = 9, b = 8 and c = x satisfies 3 cos C = 2, then : x =

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  13. In DeltaABC, if sin^2 A+ sin^2 B = sin^2 C, then the triangle is

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  14. The lengths of the sides of a triangle are alpha-beta, alpha+beta and ...

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  15. In any triangle A B C , prove that: (1+cos(A-B)cos C)/(1+cos(A-C)cos B...

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  16. If the sides of a triangle ABC are in AP and 'a' is the smallest side,...

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  17. In a DeltaABC, a ^(2) cos 2B+b^(2) cos 2A+2ab cos (A-B) is equal to?

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  18. In any DeltaABC, 2 [bc cos A + ca cos B+ ab cos C]=

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  19. In a DeltaABC, tan ""1/2 (A+B) . Cot""1/2(A-B) is equal to ?

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  20. If in a Delta ABC, b =sqrt3, c=1 and B-C =90^(@), then angle A is

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