posted by greg
Hi, I was working on my math homework and I was stumbling on these problems. I wanted to double check my answers that I have; I also could not answer 5.
If vectors O(0,0,0), A(6,0,0), B(6,-sqrt(24), sqrt(12)), and C(0,-sqrt(24), sqrt(12)) form a square.
1) Find a vector equation of the line L, through M (the midpoint of OB), perpendicular to the plane II.
For this I got L = (3, -sqrt24/2, sqrt12/2) + t (0, 1, sqrt2).
2) Find the coordinates of D, the point of intersection of the line L with the plane whose equation is y = 0.
For this I got D=(3,sqrt24/2, sqrt12/2 + 3)
3) Find the coordinates of E, the reflection of the point D in the plane II.
I got E = (-3, -sqrt24/2, -sqrt12/2+3)
4) Find the angle of ODA, and what this tells you about the solid OABCDE.
I couldn't get this because my cos0 was 5.