11Bhaiya, are there pairs of straight lines in 3D geo as well? [2]
what is the angle between lines whose Dr's are given by
l+m+n=0
l2+m2-n2=0
i have read this same question 4 places but neither time could i understand what it means .Plz help...
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6 Answers
62(l/k)2+(m/k)2+(n/k)2=1
where k2 is l2+m2+n2
thus, n/k2=1/2
n/k=±1/√2
now you can take it from here....
you should reduce l, m , n as l/k and m/k and n/k respectively.
1itna toh maine bhi koshish ki thi par samajh mein hi nahi aaya ki do line kaha hai ??matlab [l m n] toh kisi ek hi line ke ho sakte hai na..
[7][7] toh angle kaise ...
i mean i couldn't understand what question means by two lines.. when [l m n] can belong to only one line in fact i didn;t understabd the quesition at all [2]
1can anyone please post the complete soln...
or is if it is too lengthy plz explain the question..
11
1l = -(n+m) --------1
put this one in the second eqn...
u will get .. 2m(m+n)=0 => m/n=0 or m/n= -1.
find l/n from 1.
now, u will get a ratio...
equalise it to some constant say.. k.
u have another eqn : l2+m2+n2=1.
put l,m,n in terms of k in this eqn.
find k..
hence find l,m,n.
u will get two values for each..
thence, find the angle in between : l1l2 + m1m2 +n1n2 = cosθ