Question 1173623
<pre>
Plug in the formula for the angle between vectors <i>u</i> and <i>v</i> where:

<i>u</i> = x<sub>1</sub><i>i</i> + y<sub>1</sub><i>j</i>
<i>v</i> = x<sub>2</sub><i>i</i> + y<sub>2</sub><i>j</i>

{{{theta}}}{{{""=""}}}{{{"tan"^(-1)}}}{{{abs((x[1]y[2]-x[2]y[1])/(x[1]x[2]+y[1]y[2]))}}}

<i>u</i> = -6<i>i</i> - 2<i>j</i>
<i>v</i> = -9<i>i</i> + 4<i>j</i>

{{{theta}}}{{{""=""}}}{{{"tan"^(-1)}}}{{{abs(((-6)(4)-(-9)(-2))/((-6)(-9)+(-2)(4)))}}}

{{{theta}}}{{{""=""}}}{{{"tan"^(-1)}}}{{{abs(((-24)-(18))/((54)+(-8)))}}}

{{{theta}}}{{{""=""}}}{{{"tan"^(-1)}}}{{{abs((-42)/(46))}}}

{{{theta}}}{{{""=""}}}{{{"tan"^(-1)}}}{{{abs(-0.9130434783)}}}

{{{theta}}}{{{""=""}}}{{{"tan"^(-1)}}}{{{(0.9130434783)}}}

{{{theta}}}{{{""=""}}}{{{42.3974378^o}}}

{{{theta}}}{{{""=""}}}{{{"42.40"^o}}}

Edwin</pre>