2011-02-04, 06:03 AM
Is the * in the first part supposed to represent a dot product/scalar product? Because you can't just multiply two vectors, lol.
If it is, then its just AdotB=A*B*Cos(theta). Solve for theta [theta = arccos(AdotB/(A*B))]
For part 2, you know the vector a, which you can imagine as being along a Hypotenuse of a triangle. Then ax and ay are the other two sides, how would you use trig functions to find the values for them normally?
parts c and d are the same thing with a shifted co-ordinate system. Just imagine (or redraw it!) to have the x axis now along ax' and the y axis along ay'. Find the new theta between a and ax', and then solve like before
If it is, then its just AdotB=A*B*Cos(theta). Solve for theta [theta = arccos(AdotB/(A*B))]
For part 2, you know the vector a, which you can imagine as being along a Hypotenuse of a triangle. Then ax and ay are the other two sides, how would you use trig functions to find the values for them normally?
parts c and d are the same thing with a shifted co-ordinate system. Just imagine (or redraw it!) to have the x axis now along ax' and the y axis along ay'. Find the new theta between a and ax', and then solve like before