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Supose directioncoisnes of two lines are...

Supose directioncoisnes of two lines are given by `ul+vm+wn=0 and al^2+bm^2+cn^2=0` where u,v,w,a,b,c are arbitrary constnts and l,m,n are directioncosines of the lines. For `u=v=w=1` if `(n_1 n_2)/(l_1 l_2)=((a+b)/(b+c))` then (A) `(m_1m_2)/(l_1 l_2)=((b+c))/((c+a))` (B) `(m_1m_2)/(l_1 l_2)=((c+a))/((b+c))` (C) `(m_1m_2)/(l_1 l_2)=((a+b))/((c+a))` (D) `(m_1m_2)/(l_1 l_2)=((c+a))/((a+b))`

A

`a+b+c=0`

B

`a^(-1)+b^(-1)+c^(-1)=0`

C

`a=b=c`

D

none of these

Text Solution

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The correct Answer is:
B
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