let 1

Question

let 1< m<3. In a triangle ABC if 2b = (m+1)a and cos A = [(m-1)(m+3)/4m] 1/2 . prove that there r 2 values for the third side one of which is m times the other.

Badiuddin askIITians.ismu Expert · Answer

Dear cos A = [(m-1)(m+3)/4m] 1/2 calculate sinA = [1-cos 2 A] 1/2 = [(m+1)(3-m)/4m] 1/2 now sinB /b =sinA /a sinB = (m+1)/2 sinA = [(m+1) 3 (3-m)/16m] 1/2 now calculate CosB = &plusmn; [1-sin 2 B] 1/2 = &plusmn; [(m-1) 3 (m+3)/16m] 1/2 now sinC =sin(180 -A-B) =sin(A+B) =sinA cosB + cosA sinB = [(m-1)(m+3)(1+m)(3-m)/16m 2 ] 1/2 [(1+m) &plusmn;(m-1)] for + value SinC = [(m-1)(m+3)(1+m)(3-m)/16m 2 ] 1/2 [2m ] for - alue sinC = [(m-1)(m+3)(1+m)(3-m)/16m 2 ] 1/2 [(2 ] clearly one value is m times the other Please feel free to post as many doubts on our discussion forum as you can. If you find any question Difficult to understand - post it here and we will get you the answer and detailed solution very quickly. We are all IITians and here to help you in your IIT JEE & AIEEE preparation. All the best. Regards, Askiitians Experts Badiuddin

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let 1 cos A = [(m-1)(m+3)/4m] 1/2 . prove that there r 2 values for the third side one of which is m times the other.

let 1< m<3. In a triangle ABC if 2b = (m+1)a and

cos A = [(m-1)(m+3)/4m]^{1/2 .} prove that there r 2 values for the third side one of which is m times the other.

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