Question 809488
Verify the identity
2cos2x-2/sin2x = cotx-secxcscx-tanx 
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Start with right side:
cotx-secxcscx-tanx 
{{{cos(x)/sin(x)-(1/cos(x))(1/sin(x))-sin(x)/cos(x)}}}
LCD:sin(x)cos(x)
{{{(cos^2(x)-1-sin^2(x))/(sin(x)cos(x))}}}
{{{(cos(2x)-1)/(sin(x)cos(x))}}}
multiply top and bottom by 2
{{{(2cos(2x)-2)/(2sin(x)cos(x))=(2cos(2x)-2)/(sin(2x))}}}

verified: right side=left side