(1)当k为奇数时,原式=sina×(-cosa)/sina×cosa= -1
当k为偶数时,原式=-sina×cosa/-sina×-cosa= -1
所以原式= -1
(2)原式=-sin(x+13pai/8-pai)- 3cos(x-19pai/8+3pai)/ [-sin(4pai-(27pai/8-x))-cos(x+21pai/8-2pai)]
=-tan(x+5兀/8)-3 /(-tan(x+5兀/8)-1)
=a-3/(-a-1)
(1)当k为奇数时,原式=sina×(-cosa)/sina×cosa= -1
当k为偶数时,原式=-sina×cosa/-sina×-cosa= -1
所以原式= -1
(2)原式=-sin(x+13pai/8-pai)- 3cos(x-19pai/8+3pai)/ [-sin(4pai-(27pai/8-x))-cos(x+21pai/8-2pai)]
=-tan(x+5兀/8)-3 /(-tan(x+5兀/8)-1)
=a-3/(-a-1)