If →r=λ(→a×→b)+μ(→b×→c)+ν(→c×→a) and [→a →b →c]=18, then λ+μ+ν is equal to
Nonzero vectors →a,→b,→c satisfy →a.→b =0, (→b−→a).(→b+→c) = 0 and 2 |→b+→c|=|→b−→a|.
If = →a=μ→b+4→c then μ = ______