Câu hỏi 2 trang 142 SGK Đại số 10
Đề bài
Tính: sin25π4;cos(−2400);tan(−4050)sin25π4;cos(−2400);tan(−4050)
Hướng dẫn giải
sin25π4=sin(6π+π4)=sinπ4=√22cos(−2400)=cos(−1800−600)=cos(−600)=cos600=12tan(−4050)=tan(−3600−450)=−tan450=−1
Tính: sin25π4;cos(−2400);tan(−4050)sin25π4;cos(−2400);tan(−4050)
sin25π4=sin(6π+π4)=sinπ4=√22cos(−2400)=cos(−1800−600)=cos(−600)=cos600=12tan(−4050)=tan(−3600−450)=−tan450=−1