I am following a derivation in a Control Theory book by Bryson and Ho,
I see a statement like,
$$ - \nabla (\lambda \cdot w) = -(\lambda \cdot \nabla) w - \lambda \times (\nabla \times w) $$
This equation is puzzling because in the Vector Calculus identities I've seen so far, there is
$$ \nabla (A \cdot B) = (A \cdot \nabla) B + (B \cdot \nabla) A + A \times (\nabla \times B) + B \times (\nabla \times A) $$
The expression two above seems a few terms short in that regards.
As far as I can tell from the problem there isn't anything special about $\lambda$ or $w$. Am I missing something?
Thanks,