If `veca, vecb, vecc` are three non - coplanar vector such that `vecaxx(vecbxxvecc)=(vecb+vecc)/(sqrt2)`, then the angle between `veca and vecb` is ……………. .

Explanation

`vecaxx(vecbxxvecc)=(vecbxxvecc)/sqrt2`
`(veca .vecc)vecb-(veca.vecb)vecc=1/sqrt2vecb+1/sqrt2vecc`
Since `vecb and vecc` are non-collinear, comparing coefficients of `vecc` on both sides of (i) , we get
`-veca.vecb=1/sqrt2or veca.vecb=-1/sqrt2`
`(1) (1) cos theta=-1/sqrt2`
Where `theta` is the angle between `veca and vecb` .therefore,
`cos theta=-1/sqrt2or cos theta=cos135^(@)or theta=135^(@)=3pi//4`