Angle between a vector and the y-axis

**IanCarney** · May 26th 2011, 04:15 PM

Determine the angle that the vector a = (12, -3, 4) makes with the y-axis.

Would I still use the dot product? I'm confused on how I would go about do it as I'm not too familiar with three dimensional vectors. All help appreciated!

**Plato** · May 26th 2011, 04:22 PM

Originally Posted by IanCarney

Determine the angle that the vector a = (12, -3, 4) makes with the y-axis.

$\mathbf{j}=<0,1,0>$ .
Find $\arccos \left( {\frac{{a \cdot j}}{{\left\| a \right\|}}} \right)$

**IanCarney** · May 26th 2011, 04:32 PM

Originally Posted by Plato

$\mathbf{j}=<0,1,0>$ .
Find $\arccos \left( {\frac{{a \cdot j}}{{\left\| a \right\|}}} \right)$

Okay I think I got it. I was doing something wrong before so I got a different answer than the book. Thanks again for all your help!

Thread: Angle between a vector and the y-axis

LinkBack

Thread Tools

Display

Angle between a vector and the y-axis

Similar Math Help Forum Discussions

Equation of Circle Tangent to Y-Axis, X-Axis and Line

Vector Angle

Angle between line and x-axis.

[SOLVED] Angle between the axis and the lines

Vector: Angle