1.
If r⃗\vec{r} and s⃗\vec{s} are non-zero constant vectors and the scalar bb is chosen such that ∣r⃗+bs⃗∣|\vec{r} + b\vec{s}| is minimum, then the value of ∣bs⃗∣2+∣r⃗+bs⃗∣2|b\vec{s}|^2 + |\vec{r} + b\vec{s}|^2 is equal to