If the volume of parallelopiped formed by the vectors  i^+λj^+k^,j^+λk^ and λi^+k^   is minimum, then 20213λ is

Given vectors are  i^+λj^+k^,j^+λk^ and λi^+k^ which forms a parallelopiped.Volume of the parallelopiped isV=1λ101λλ01=1+λ3−λ⇒V=λ3−λ+1On differentiating w.r.t. λ, we getdVdλ=3λ2−1For maxima or minima, dVdλ=0⇒λ=±13and d2Vdλ2=6λ=23>0, for  λ=13-23<0, for λ=−13∵d2Vdλ2 positive for λ=13, hence volume V is minimum for λ=13