0,π/6,π/4,π/3,π/3,π/2,2/3π,3/4π,5/6π,π,7/6π的正弦余弦值是多少?

Question

0,π/6,π/4,π/3,π/3,π/2,2/3π,3/4π,5/6π,π,7/6π的正弦余弦值是多少?

Answer 1

sin0=0
sinπ/6=1/2
sinπ/4=√2/2
sinπ/3=√3/2
sinπ/2=1
sin2/3π=sin(π-1/3π)=sin1/3π=√3/2
sin3/4π=sin(π-1/4π)=sin1/4π=√2/2
sin5/6π=sin(π-1/6π)=sin1/6π=1/2
sinπ=0
sin7/6π=sin(π+1/6π)=-sin1/6π=-1/2
cos0=1
cosπ/6=√3/2
cosπ/4=√2/2
cosπ/3=1/2
cosπ/2=0
cos2/3π=cos(π-1/3π)=cos1/3π=1/2
cos3/4π=cos(π-1/4π)=cos1/4π=√2/2
cos5/6π=cos(π-1/6π)=cos1/6π=√3/2
cosπ=-1
cos7/6π=cos(π+1/6π)=-cos1/6π=-√3/2
楼主,这些常见的是要背的,如果你要推要结合三角形