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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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The correct Answer is:
`C_(1)^(2)+ C_(2)^(2)-2C_(1), C_(2)cos A = 4a^(2)cos A`
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ARIHANT MATHS ENGLISH-PROPERTIES AND SOLUTION OF TRIANGLES -Exercise (Questions Asked In Previous 13 Years Exam)
  1. If a, b and A are given in a triangle and c(1), c(2) are possible valu...

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  2. In a triangle XYZ, let x, y, z be the lengths of sides opposite to the...

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  3. In a triangle the sum of two sides is x and the product of the same is...

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  4. Consider a triangle A B C and let a , ba n dc denote the lengths of th...

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  5. about to only mathematics

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  6. Let PQR be a triangle of area Delta with a = 2, b = 7//2, and c = 5//2...

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  7. If the angle A ,Ba n dC of a triangle are in an arithmetic propression...

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  8. Let A B C be a triangle such that /A C B=pi/6 and let a , b and c deno...

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  9. A triangle A B C with fixed base B C , the vertex A moves such that co...

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  10. Let A B Ca n dA B C ' be two non-congruent triangles with sides A B=4,...

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  11. A straight line through the vertex P of a triangle P Q R intersects th...

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  12. Consider the circle x^2 + y^2 = 9 and the parabola y^2 = 8x. They inte...

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  13. Consider the circle x^2 + y^2 = 9 and the parabola y^2 = 8x. They inte...

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  14. Consider the circle x^2 + y^2 = 9 and the parabola y^2 = 8x. They inte...

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  15. Internal bisector of /A of triangle ABC meets side BC at D. A line dra...

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  16. One angle of an isosceles triangle is 120^0 and the radius of its incr...

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  17. In Delta ABC, which one is true among the following ?

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  18. Let a vertical tower A B have its end A on the level ground. Let C be ...

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  19. ABCD is a trapezium such that AB and CD are parallel and BC bot CD. If...

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  20. For a regular polygon, let r and R be the radii of the inscribed and t...

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  21. In triangle A B C , let /c=pi/2dot If r is the inradius and R is circu...

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