One problem with 3d x,y,z resultant questions

[hisoko]

So this first question

http://tinypic.com/view.php?pic=2qls4s4&s=4

I figured out F1 X,Y,Z but for F2 I cannot seem to figure it out at all, it seems impossible. I can only figure out the Y axis but not the X and Z, any ideas?

 

[tiny-tim]

Hi hisoko!

Hint: call the unit vector in the F₂ direction (a,b,c).

Then you know that the angle between (a,b,c) and (0,0,1), and the angle between (a,b,c) and (0,1,0), are both 60º.