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If a, b and A are given in a triangle and `c_(1), c_(2)` are possible values of the third side, then prove that `c_(1)^(2) + c_(2)^(2) - 2c_(1) c_(2) cos 2A = 4a^(2) cos^(2)A`

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ARIHANT MATHS-PROPERTIES AND SOLUTION OF TRIANGLES -Exercise (Single Integer Answer Type Questions)
  1. If in Delta ABC, / C=pi/8, a= sqrt2 and b= sqrt(2+sqrt2) then find the...

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  2. If in A B C ,A=pi/7,B=(2pi)/7,C=(4pi)/7 then a^2+b^2+c^2 must be R^2 ...

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  3. If A, B, C the angles of an acute angled Delta ABCand D=|{:((tan B+ ta...

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  4. In a DeltaABCP and Q are the mid-point or AB and AC, respectively. If ...

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  5. With usual notation in Delta ABC, the numerical value of ((a+b+c)/(r...

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  6. D is midpoint of BC in Delta ABC such that AD and AC are perpendicular...

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  7. In a triangle ABC, medians AD and CE are drawn. If AD=5, angle DAC=pi/...

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  8. In Delta ABC, (r )/(r(1))=1/2, then the valur of 16 (sum tan ((A)/(2))...

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  9. In a DeltaABC, the maximum value of 120((sum a cos ^(2)((A)/(2)))/(a+...

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  10. The sides of a triangle arr three consective natural numbers and its l...

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  11. In DeltaABC, angle C = 2 angle A, and AC = 2BC, then the value of (a^(...

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  12. If a, b and A are given in a triangle and c(1), c(2) are possible valu...

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  13. In triangle ABC, a=5, b=4, c=3. G is the centroid of trianggle. If R(...

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  14. A triangle A B C is inscribed in a circle with centre at O , The lines...

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  15. In Delta ABC, a ge b ge c and if (a^(3) +b^(2)+ c^(2))/(sin ^(3) A sin...

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  16. In a cyclic quadrilateral PQRS, PQ= 2 units, QR= 5 units, RS=3 units ...

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