Question 790863
[sin(b + pi)]/[sin (b)]


[sin(b)cos(pi) + cos(b)sin(pi)]/[sin (b)]


[sin(b)(-1) + cos(b)(0)]/[sin (b)]


[-sin(b) + 0]/[sin (b)]


[-sin(b)]/[sin (b)]


<font color="red">-1</font>


-------------------------------------------------------


So [sin(b + pi)]/[sin (b)] = <font color="red">-1</font> for all allowed values of b in the domain.