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
.
依次类似