Question 893849
I assume you mean {{{sin(theta)=-4/5}}}?
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{{{tan(theta)=sin(theta)/cos(theta)}}}
{{{cos(theta)=sin(theta)/tan(theta)}}}
{{{cos(theta)=(-4/5)/(4/3)}}}
{{{cos(theta)=(-4/5)*(3/4)}}}
{{{highlight(cos(theta)=-3/5)}}}