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If 1/2,1/3,n are direction cosines of a ...

If `1/2,1/3,n` are direction cosines of a line, then the value of `n` is

A

`sqrt(23)/6`

B

`(23)/6`

C

`2/3`

D

`3/2`

Text Solution

Verified by Experts

The correct Answer is:
A
If `(1/2,1/3,n)` are the DC's of line, then then using the relation
`l^?2+m^2+n^2=1` we get
`(1/2)^2+(1/3)^2+n^2=1`
`rArr" "n^2=1-1/4-1/9`
`rArr" "n^2=(23)/(36)rArrn=pm(sqrt(23))/6`
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