哪位告诉我一下15度和75度的三角函数值?

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哪位告诉我一下15度和75度的三角函数值?

sin15=cos75=(√6-√2)/4
cos15=sin75=(√6+√2)/4
tan15=cot75=2-√3
tan75=cot15=2+√3

cos75
=sin15
=sin(45-30)
=sin45cos30-cos45sin30
=(√2/2)*(√3/2)-(√2/2)*(1/2)
=√6/4-√2/4
=(√6-√2)/4
=0.258819045102521
同理:
cos15
=sin75
=sin(45+30)
=sin4...

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cos75
=sin15
=sin(45-30)
=sin45cos30-cos45sin30
=(√2/2)*(√3/2)-(√2/2)*(1/2)
=√6/4-√2/4
=(√6-√2)/4
=0.258819045102521
同理:
cos15
=sin75
=sin(45+30)
=sin45cos30+cos45sin30
=(√2/2)*(√3/2)+(√2/2)*(1/2)
=√6/4+√2/4
=(√6+√2)/4
=0.965925826289068

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