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If alpha, beta, gamma are lenghts of int...

If `alpha, beta, gamma` are lenghts of internal bisectors of angles A,B,C respectively of `DeltaABC`, then `sum (1)/(alpha) "cos" (A)/(2)` is

A

a+b+c

B

`(1)/(a)+(1)/(b)+(1)/(c)`

C

`2((1)/(a)+(1)/(b)+(1)/(c))`

D

`2(a+b+c)`

Text Solution

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The correct Answer is:
B
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AAKASH SERIES-REVISION EXERCISE-PROPERTIES OF TRIANGLES
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  2. If R is the circumradius of equilateral traingle DeltaABC then circumr...

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  3. If alpha, beta, gamma are lenghts of internal bisectors of angles A,B,...

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  4. In DeltaABC, a=2b,|A-B|=(pi)/(3) then angle C=

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  5. In Delta ABC , if x=tan((B-C)/(2))tan.(A)/(2),y=tan((C-A)/(2))tan.(B)/...

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  6. In a triangle ABC, D and E are the mid-points of BC, CA respectively. ...

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  7. The alternate vertices of a regular hexagon are joined to form another...

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  8. In DeltaABC if r(1)=2r(1)=3r(3) and D is the mid point of BC then cos ...

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  9. If (sin 3B)/(sinB)=((a^(2)-c^(2))/(2ac)) then a^(2),b^(2),c^(2) are in

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  10. In DeltaABC if r(1)=R then

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  11. IF Delta ABC,if a tan A+b tan B=(a+b) tan ((A+B)/2), then the triangle...

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  12. In triangle ABC, D is mid point of BC, if 'AD' is perpendicular to 'AC...

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  13. The sides of a right angled triangle are in A.P then they are in the r...

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  14. If the bisector angle A of the triangle ABC makes an angle theta with ...

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  15. In DeltaABC, AD is the altitude from A, if b gt c, C=23^(0), AD=(abc)/...

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  16. In DeltaABC, a=6,b=4 and cos (A-B)=4//5 then its area is

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  17. In a triangle ABC, medians AD and BE are drawn.IF angle D=4, angle DAB...

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  18. If the area of an isosceles triangle is sqrt2+1are vertical angle is 4...

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  19. In DeltaABC, if a=7 b=8, c=9 then the distance from the vertex B to th...

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  20. If the median of DeltaABC through A is perpendicular to AB then tan A+...

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