✨ 最佳解答 ✨
tan(260)=tan(180+80)=tan(80)
sin(1970)=sin(360*5+170)=sin(170)
=sin(10)=-sin(80)
tan(80)=sin(80)/cos(80)=k/1
sin(80)=k/√(1+k^2)
所求sin(1970)=-sin(80)=-k/√(1+k^2)
尷尬我修正一下
tan(260)=tan(180+80)=tan(80)
sin(1970)=sin(360*5+170)=sin(170)
=sin(10)=cos(80)
tan(80)=sin(80)/cos(80)=k/1
cos(80)=1/√(1+k^2)
所求sin(1970)=cos(80)=1/√(1+k^2)
sin(1970)=sin(360*5+170)=sin(170)
=sin(10)=「-sin(80)」
這邊換到壞掉…應該要是cos(80)
好哦 謝謝😊
答案的分子是1欸🤔