If l,m,n and a,b,c are direction cosines of two lines then
they are parallel when la + mb + nc = 0
they are perpendicular when
the direction ratios of the bisectors of the angles between l±a, m±b, n±c
the direction ratios of the bisectors of the angles between l±a, m±b, n±c
The correct option is: (C) the direction ratios of the bisectors of the angles between l±a, m±b, n±c
Let be a twice differentiable function such that for all . If and satisfies , where , then the area of the region R = {(x, y) | 0 y f(ax), 0 x 2\ is :
For , the largest positive integer that divides is . If is the sum of all positive divisors of , then find .