3. (CS application: computer graphics) Ray tracing is a way to render images that sim- ulates the effect of light sources. This requires understanding the angle in which the light strikes the simulated surface. To do this, the normal vector is found. The normal vector is orthogonal to the surface (see https://en.wikipedia.org/wiki/Normal-(geometry) #/media/File : Surface-normals. svg) How do we do this? If we have a plane represented by vectors a= [xa, ya,,a] and b/xb,yb,al, then
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