数学原理
cos(a)cos(b)=1/2 * (cos(a+b)+cos(a-b))
sin(a)sin(b)=1/2 * (cos(a-b)-cos(a+b))
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x=cos(a),y=cos(b)
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1.5732*3.5762 = 100 * 0.15732 * 0.35762
cos(80D56'55'') = 0.15732
cos(69D2'45'') = 0.35762
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cos(149D59'40'') = -0.86598
cos(11D54'11'') = 0.97850
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类似原理,除法可以用sec等
cos(a)cos(b)=1/2 * (cos(a+b)+cos(a-b))
sin(a)sin(b)=1/2 * (cos(a-b)-cos(a+b))
------------------------------------------------
x=cos(a),y=cos(b)
------------------------------------
1.5732*3.5762 = 100 * 0.15732 * 0.35762
cos(80D56'55'') = 0.15732
cos(69D2'45'') = 0.35762
--------------------------------
cos(149D59'40'') = -0.86598
cos(11D54'11'') = 0.97850
---------------------------------------------
类似原理,除法可以用sec等