If `( vec axx vec b)xx( vec bxx vec c)= vec b ,w h e r e vec a , vec b ,a n d vec c` are nonzero vectors, then 1.` vec a , vec b ,a n d vec c` can be coplanar 2.` vec a , vec b ,a n d vec c` must be coplanar 3.` vec a , vec b ,a n d vec c` cannot be coplanar 4.none of these

Options

A. `veca,vecb and vecv` can be coplanar
B. `veca, vecb and vecc` must be coplanar
C. `veca,vecb and vecc` cannot be coplanar
D. none of these

Answer

c

Explanation

`(veca xx vecb) xx (vecb xx vecc) = vecb`
` or [veca vecb vecc] vecb = vecb`
` or [veca vecb vecc] =1 `
therefore, `veca , vecb and vecc` cannot be coplanar.