Question

Without using calculator find :
cos(225) sin(315) + sin( –270) tan(405)

Answer 1

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/
`√(2)` *(-1/
`√(2)`) + (-(-1)*(-(1)

=1/2+1

=1+2/3

=3/3

=1