Advertisement

Show that lines:
straight r with rightwards arrow on top space equals space straight i with hat on top space plus straight j with hat on top space plus straight k with hat on top space plus space straight lambda open parentheses straight i with hat on top minus straight j with hat on top space plus space straight k with hat on top close parentheses
straight r with rightwards arrow on top space equals space 4 straight j with hat on top space plus space 2 straight k with hat on top space plus space straight mu open parentheses 2 straight j with hat on top minus straight j with hat on top plus 3 straight k with hat on top close parentheses space are space coplanar.
Also, find the equation of the plane containing these lines. 


straight r with rightwards arrow on top space equals space straight i with hat on top space plus space straight j with hat on top space plus space straight k with hat on top space plus space straight lambda left parenthesis straight i with hat on top minus straight j with hat on top plus straight k with hat on top right parenthesis space... left parenthesis straight i right parenthesis
Converting into cartesian form,
fraction numerator straight x minus 1 over denominator 1 end fraction space equals fraction numerator straight y minus 1 over denominator negative 1 end fraction equals fraction numerator straight z minus 1 over denominator 1 end fraction
left parenthesis straight x subscript 1 comma space straight y subscript 1 comma space straight z subscript 1 right parenthesis space equals space left parenthesis 1 comma space 1 comma space 1 right parenthesis
straight a subscript 1 space equals space 1 comma space space straight b subscript 1 space equals negative 1 comma space space straight c subscript 1 space equals 1
straight r with rightwards arrow on top equals 4 straight j with hat on top plus 2 straight k with hat on top plus straight mu left parenthesis 2 straight i with hat on top minus straight j with hat on top plus 3 straight k with hat on top right parenthesis space space space... left parenthesis ii right parenthesis 
Converting into cartesian form,
fraction numerator straight x minus 0 over denominator 2 end fraction equals fraction numerator straight y minus 4 over denominator negative 1 end fraction equals fraction numerator straight z minus 2 over denominator 3 end fraction
left parenthesis straight x subscript 2 comma space straight y subscript 2 comma space straight z subscript 2 right parenthesis space equals space left parenthesis 0 comma space 4 comma space 2 right parenthesis
straight a subscript 2 equals space 2 comma space space straight b subscript 2 equals negative 1 comma space space straight c subscript 2 equals 3
Condition for the lines to be coplanar is
open vertical bar table row cell 0 minus 1 end cell cell space 4 minus 1 end cell cell space 2 minus 1 end cell row 1 cell negative 1 end cell 1 row 2 cell negative 1 end cell 3 end table close vertical bar space equals space open vertical bar table row cell negative 1 end cell cell space space 3 end cell cell space space 1 end cell row 1 cell negative 1 end cell cell space space 1 end cell row 2 cell negative 1 end cell cell space space 3 end cell end table close vertical bar equals 0
therefore space the space lines space are space coplanar.
Intersection space of space the space two space lines space is
Let space the space equation space be space straight a left parenthesis straight x minus straight x subscript 1 right parenthesis plus straight b left parenthesis straight y minus straight y subscript 1 right parenthesis plus straight c left parenthesis straight z minus straight z subscript 1 right parenthesis space equals space 0 space... left parenthesis iii right parenthesis
Direction space ratios space of space the space plane space is
straight a minus straight b plus straight c equals 0
2 straight a minus straight b plus 3 straight c space equals 0
Solving space by space cross minus multiplication comma
fraction numerator straight a over denominator negative 3 plus 1 end fraction equals fraction numerator straight b over denominator 2 minus 3 end fraction equals fraction numerator straight c over denominator negative 1 plus 2 end fraction
straight a equals negative 2 straight lambda comma space space straight b equals negative straight lambda comma space space straight c equals straight lambda
Since the plane passes through (0, 4, 2) from line (ii)
straight a left parenthesis straight x minus 0 right parenthesis plus straight b left parenthesis straight y minus 4 right parenthesis plus straight c left parenthesis straight z minus 2 right parenthesis space equals 0
rightwards double arrow space minus 2 λx minus straight lambda left parenthesis straight y minus 4 right parenthesis plus straight lambda left parenthesis straight z minus 2 right parenthesis space equals 0
rightwards double arrow space minus 2 straight x minus straight y plus 4 plus straight z minus 2 equals 0
rightwards double arrow negative 2 straight x minus straight y plus straight z equals negative 2
rightwards double arrow 2 straight x plus straight y minus straight z equals 2

477 Views

Advertisement

Three Dimensional Geometry

Hope you found this question and answer to be good. Find many more questions on Three Dimensional Geometry with answers for your assignments and practice.

Mathematics Part II

Browse through more topics from Mathematics Part II for questions and snapshot.