A plane mirror is placed at the origin so that the direction ratios of its normal are (1$$, $$-1$$, $$1). A ray of light, coming along the positive direction of the $$x-axis$$ strikes the mirror. Then the direction ratios of the reflected ray are

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Let (l$$, m, $$n) be the d.c’s of reflected ray We have (1$$, $$0$$, $$0) are the d.c’s of incident ray (x-axis).D.c’s of normal are $$13$$,−$$13$$,$$13Let$$ (l1$$,$$m1$$,$$n1)=(l$$,m,$$n),$$(l2$$,$$m2$$,$$n2)=(1$$,$$0$$,$$0)If$$ θ is the angle between the normal to the plane and incident ray, then $$cos$$θ$$=13$$  $$l1+l22cos$$θ,$$m1+m22cos$$θ,$$n1+n22cos$$θ$$=(l$$,m,$$n)l+12cos$$θ$$=13$$⇒$$l=$$−$$13m$$−$$02cos$$θ$$=$$−$$13$$⇒$$m=$$−$$23$$  $$n+02cos$$θ$$=13$$⇒$$n=23$$

A plane mirror is placed at the origin so that the direction ratios of its normal are (1, -1, 1). A ray of light, coming along the positive direction of the x-axis strikes the mirror. Then the direction ratios of the reflected ray are

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