Answer:
Step-by-step explanation:
cos(225)*sin(315) + sin(-270)*tan(405)
=cos(360-135)*sin(360-45) + (-sin(360-90)*tan(180*3-135)
=cos135*(-sin45) + (-(-sin90)*(-cot135)
=-1/[tex]\sqrt{2}[/tex] *(-1/[tex]\sqrt{2}[/tex]) + (-(-1)*(-(1)
=1/2+1
=1+2/3
=3/3
=1
