`L_(1)` and `L_(2)` are two lines.If the reflection of `L_(1)` on `L_(2)` and the reflection of `L_(2)` on `L_(1)` coincide,then the angle between the lines

L_1a n dL_2 are two lines. If the reflection of L_1onL_2 and the reflection of L_2 on L_1 coincide, then the angle between the lines is (a) 30^0 (b) 60^0 45^0 (d) 90^0

Given equation of line L_(1) is y = 4. (iii) Find the equation of L_(2) .

In the network in given find l_(1), l_(2) and l.

If lt l_(1), m_(1), n_(1)gt and lt l_(2), m_(2), n_(2) gt be the direction cosines of two lines L_(1) and L_(2) respectively. If the angle between them is theta , the costheta=?

Points (4,0) and (-3,0) are invarient points under reflection in line L_1 , point (0,5) and (0,-2) are invarient under reflection in line L_2. Write P' . The reflection of P(6,-8) " in " L_1 and P'' the image of P " in " L_2 .

The equation of line l_(1) is y=2x+3 , and the equation of line l_(2) is y=2x-5.

Let L be the set of all straight lines in plane. l_(1) and l_(2) are two lines in the set. R_(1), R_(2) and R_(3) are defined relations. (i) l_(1)R_(1)l_(2) : l_(1) is parallel to l_(2) (ii) l_(1)R_(2)l_(2) : l_(1) is perpendicular to l_(2) (iii) l_(1) R_(3)l_(2) : l_(1) intersects l_(2) Then which of the following is true ?

Let l_(1) and l_(2) be the two skew lines. If P, Q are two distinct points on l_(1) and R, S are two distinct points on l_(2) , then prove that PR cannot be parallel to QS.

STATEMENT-1 : If a line making an angle pi//4 with x-axis, pi//4 with y-axis then it must be perpendicular to z-axis and STATEMENT-2 : If direction ratios of two lines are l_(1), m_(1), n_(1) and l_(2), m_(2), n_(2) then the angle between them is given by theta = cos ^(-1)(l_(1)l_(2)+m_(2)m_(2)+n_(1)n_(2))

Consider three planes P_(1):x-y+z=1 , P_(2):x+y-z=-1 and P_(3):x-3y+3z=2 . Let L_(1),L_(2),L_(3) be the lines of intersection of the planes P_(2) and P_(3),P_(3) and P_(1),P_(1) and P_(2) respectively. Statement I Atleast two of the lines L_(1),L_(2) and L_(3) are non-parallel. Statement II The three planes do not have a common point.