Question 627975
I must assume that the "x/2" is supposed to be {{{pi/2}}}. If what you posted is correct then I see no way to solve this.<br>
{{{cot(theta-pi/2) = -tan(theta)}}}
Probably the quickest way to solve this is based on recognizing that {{{theta - pi/2 = -(pi/2 - theta)}}}. Substituting this in we have:
{{{cot(-(pi/2-theta)) = -tan(theta)}}}
Next we use the odd/even property for cot, cot(-x) = - cot(x), which allows us to "move" the negative out of the argument:
{{{-cot(pi/2-theta) = -tan(theta)}}}
Next we use another identity: {{{cot(pi/2-x) = tan(x)
{{{-tan(theta) = -tan(theta)}}}
And we're finished!