26 Oct
2007
26 Oct
'07
6:32 p.m.
On Saturday 27 October 2007, Marc LeBrun wrote:
=Bill Gosper 1) Two blips on the radar are exactly a mile away and 40 deg apart. How far apart are they?
Or, "The sun is roughly 100 million miles away and looks half a degree wide. About how big is it?"
But I'm not getting how these are cubic?
The answer is 2 miles * sin 20 degrees, and sin 20 degrees satisfies a cubic equation over Z because sin (3*20 degrees) = 1/2. So if knowing what equation the answer satisfies is more important to you than knowing it to (say) five significant figures, then this is a problem involving cubic equations. I'll hazard a guess that anyone who feels that way *already* sees value in understanding cubic equations. -- g