Question 736258
sin2x=cosx
{{{sin(2x) = cos(x)}}}
{{{2sin(x)*cos(x) = cos(x)}}}
{{{2sin(x)cos(x) -  cos(x)= 0}}}
{{{2sin(x)cos(x) -  cos(x)= 0}}}
{{{cos(x)*(2sin(x) - 1) = 0}}}
cos(x) = 0
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2sin(x) - 1 = 0
sin(x) = 1/2
You can finish and check.