Use cross product to find the sine of the angle between the vectors

u (2,3,-6)

v(2,3,6)

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- Oct 24th 2009, 09:25 AMdaphnewoonVector question 2
Use cross product to find the sine of the angle between the vectors

u (2,3,-6)

v(2,3,6)

- Oct 24th 2009, 10:22 AMearboth
- Oct 24th 2009, 07:55 PMdaphnewoon
Hello, thanks for replying

I know the formula to solve this question, just that i've gt this equation:

(36 , -30, 0) = 10 sin alpha

How am i going to manipulate this? - Oct 24th 2009, 11:55 PMearboth
I'm not sure how you got this result ... (Thinking)

Use the formula I posted in my previous answer:

$\displaystyle

|\vec u \times \vec v|= |\vec u| \cdot |\vec v| \cdot \sin(\vec u, \vec v)

$

Plug in all the values you know:

$\displaystyle |(2,3,-6) \times (2,3,6)|= |(2,3,-6)| \cdot |(2,3,6)| \cdot \sin(\vec u, \vec v)$

$\displaystyle |(36, -24, 0)|= 7 \cdot 7 \cdot \sin(\vec u, \vec v)$

$\displaystyle 12 \cdot \sqrt{13}= 49 \cdot \sin(\vec u, \vec v)$

... and now solve for $\displaystyle \sin(\vec u, \vec v)$