if l1,m1,n1 and l2,m2,n2 are the d.c.'s of two mutually perpendicular lines,show that the d.c.'s of the line perpendicular to both of these are m1n2-m2n1,nil2-n2l1,l1m2-l2m1

Asked by prabhakar p | 13th Mar, 2013, 09:18: AM

Expert Answer:

It is a simple formula. You can expand it and show that LHS = RHS. 
 
Or else, you can simply expand the denominator in the equation 4 and regroup the terms and you should reach what is written on the LHS here. 

Answered by  | 14th Mar, 2013, 07:33: AM

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