Question

请教数学三角函数非规则角运算.求sin(60+10){1-(根号3)tan(60-10)}的值.注意,我是用手机看答案的

Answer 1

sin(60+10){1-(根号3)tan(60-10)}

=sin70{1-(根号3)tan50}

=2sin70(sin30-cos30tan50)

=2sin70(sin30cos50-cos30sin50)/cos50

=2sin70sin(30-50)/cos50

=-2cos20sin20/sin40

=-sin40/sin40

=-1