Everyone!
I've a problem that asks
Is there any 3D-vector that forms angles of 30 and 45 degrees with x-axis and y-axis, respectively?
My attempt was using the directional cosines, and I got that the square of the angle between the vector and the z-axis is negative, so it doesn't exist! However, is this a valid way to prove that this vector does not exist?
Thanks in advance :)