An angle between the lines whose direction cosines are gien by the equations, $l$ + 3m + 5n = 0 and 5$l$m $-$ 2mn + 6n$l$ = 0, is :

Question

An angle between the lines whose direction cosines are gien by the equations,
$l$ + 3m + 5n = 0 and 5$l$m $-$ 2mn + 6n$l$ = 0, is :

${\cos ^{ - 1}}\left( {{1 \over 3}} \right)$

${\cos ^{ - 1}}\left( {{1 \over 4}} \right)$

${\cos ^{ - 1}}\left( {{1 \over 6}} \right)$

${\cos ^{ - 1}}\left( {{1 \over 8}} \right)$

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