数学三角函数化简求值,tan70cos10(根号3tan20-1)

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数学三角函数化简求值,tan70cos10(根号3tan20-1)
数学三角函数化简求值,
tan70cos10(根号3tan20-1)

数学三角函数化简求值,tan70cos10(根号3tan20-1)
tan70cos10*(√3tan20-1)
=sin70/cos70*cos10*(√3sin20/cos20-1)
=cos20/sin20*cos10*(√3sin20-cos20)/cos20
=cos10*(√3sin20-cos20)/sin20
=(√3sin20-cos20)/(2sin10)
=(1/sin10)*(sin20cos30-cos20sin30)
=1/sin10*sin(20-30)
=-1