Where did the blue box vector come from in the vector multiplication problem?

[influx]

Homework Statement

Homework Equations

R_AO = b(Sinβj+Cosβk)

The Attempt at a Solution

[/B]
The box in red is ω. However I am unsure of where they got the box in blue from? As mentioned above, R_AO = b(Sinβj+Cosβk) so not sure where they got the box in blue from? I know of the vector triple product: A x (B x C) = (A•C)B - (A.B)C, but this isn't what they've done?

Thanks

 

[pasmith]

Homework Statement

Homework Equations

R_AO = b(Sinβj+Cosβk)

The Attempt at a Solution

[/B]
The box in red is ω. However I am unsure of where they got the box in blue from? As mentioned above, R_AO = b(Sinβj+Cosβk) so not sure where they got the box in blue from? I know of the vector triple product: A x (B x C) = (A•C)B - (A.B)C, but this isn't what they've done?

Thanks

I would assume that they are doing the obvious thing, ie. calculating $\mathbf{\omega} \times \mathbf{r}_{AO}$ first, and given the presence of a scalar factor of $b$ (which goes missing in the second line before reappearing in the third) the vector in the blue box must therefore be $$\frac{\mathbf{\omega} \times \mathbf{r}_{AO}}{b}.$$ (Although given that something did go missing partway through I would recommend double-checking this.)