Question 499480
<pre>
First we'll simplify the expression using our knowledge of sines
of negative angles, double angle formula, and {{{pi="180°"}}}:

{{{sin(-61pi/12)=-sin(61pi/12)=-sin(61*"180°"/12)=-sin("915°")=""}}}

   <u>   2</u>
360)915
    <u>720</u>
    195 

{{{""=-sin("195°") = -sin("180°+15°")=-(sin("180°")cos("15°")+cos("180°")sin("15°"))=""}}}

{{{-(0*cos("15°")+(-1)*sin("15°"))=-(0-sin("15°"))=-(-sin("15°"))=sin("15°")=""
}}}

{{{sin("45°"-"30°")= sin("45°")cos("30°")-cos("45°")sin("30°")=

expr(sqrt(2)/2)expr(sqrt(3)/2)-expr(sqrt(2)/2)expr(1/2)="" }}}

{{{sqrt(6)/4-sqrt(2)/4 = (sqrt(6)-sqrt(2))/4}}}



Edwin</pre>