Question 1040921
{{{sin(x+y)=sin(x)cos(y)+cos(x)sin(y)}}}
So then,
{{{Asin(x)cos(y)=-3sin(x)}}}
{{{Acos(y)=-3}}}
and
{{{Acos(x)sin(y)=-1cos(x)}}}
{{{Asin(y)=-1}}}
Then,
{{{A^2*cos^2(y)+A^2*sin^2(y)=9+1}}}
{{{A^2=10}}}
{{{A=0 +- sqrt(10)}}}
and
{{{tan(y)=(Asin(y))/(Acos(y))}}}
{{{tan(y)=-1/(-3)}}}
{{{y=0.322}}}
So then,
{{{-3sin(x)-cos(x)=-sqrt(10)*sin(x+0.322)}}}
{{{A=-sqrt(10)}}}
{{{phi=tan^(-1)(1/3)}}}