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If A+B+C+D=pi, then the value of sumcosA...

If A+B+C+D=`pi,` then the value of `sumcosAcosC-sumsinA sinC`is

A

-1

B

1

C

2

D

0

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The correct Answer is:
D
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PATHFINDER-SOLUTION OF TRIANGLE AND HEIGHT AND DISTANCE-QUESTION BANK
  1. If in a triangle ABC, B =(2pi)/3, then cosA +cosC lies in

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  2. In a triangle ABC, sinA+sinB+sinC=1+sqrt2 and cosA+cosB+cosC=sqrt2. Th...

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  3. If A+B+C+D=pi, then the value of sumcosAcosC-sumsinA sinCis

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  4. If ina triangle ABC, b+c=3a, then cot(B/2)cot (C/2) is equal to

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  5. In a triangle ABC, sqrta+sqrtb-sqrtc is

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  6. The area of the triangle inscribed in a circle of radius 4 and the rat...

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  7. The perimeter of a triangle ABC is 6 times the Arithmetic Mean of the ...

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  8. If in an obtuse angled triangle the obtuse angle is (3pi)/4 and the ot...

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  9. The radius of the circle passing through the centre of incircle of...

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  10. In a DeltaABC, b^2+c^2=1999a^2, then (cotB+cotC)/cotA is equal to

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  11. In a DeltaABC, tanAtanBtanC=9. For such tiangle , if tan^2A+tan^2B+ta...

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  12. If in a DeltaABC, r1r2+r2r3+r3r1 is equal to (where r1,r2,r3 are the...

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  13. In a DeltaABC, 2cosA=sinB/sinCand 2^(tan^2B) is a solution of equlatio...

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  14. The area of the circle and the area of a regular polygon inscribed th...

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  15. If there are only two linear function f and g which map [1.2] on [4,6]...

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  16. If A ,B,C,D are the angle of quadrilateral, then (sumtanA)/(sumcotA)is...

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  17. If Delta be the area of a triangle ABC and length of its two sides are...

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  18. Which of the following pieces of data does not uniquely determine acut...

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  19. In a triangle ABC, (a+b+c)(b+c-a)=kbc if

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  20. If cosA/a=cosB/b=cosC/cand the side a=2, then area of triangle is

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