Question 312176
{{{cos(2x)=1-2*(sin(x))^2=1-2S^2}}}
{{{3cos(2x)=3-6S^2}}}
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{{{3*cos2x+sinx-1=3-6S^2+S-1=0}}}
{{{-6S^2+S+2=0}}}
{{{6S^2-S-2=0}}}
{{{(3S+2)(2S-1)=0}}}
Two solutions:
{{{3S-2=0}}}
{{{3S=2}}}
{{{S=2/3}}}
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{{{2S+1=0}}}
{{{2S=-1}}}
{{{S=-1/2}}}
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The angles whose {{{sin(A)=2/3}}} are {{{41.8}}} and {{{138.2}}}.
The angles whose {{{sin(A)=-1/2}}} are {{{210}}} and {{{330}}}.