sin10º,sin20º,sin30º,sin35º.和cos,tan,如何算.如sin80°=0.9848

sin80=0.9848
cos80=√(1-sin²80)=0.1736
sin10=sin(90-80)=cos80=0.1736
cos10=sin80=0.9848
sin20=2sin10cos10=2*0.9848*0.1736=0.3419
cos20=√(1-sin²20)=0.9397
sin30=0.5
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依次类似