Question 1036146
{{{cot^2(theta)*(sec^2(theta) - 1) = cot^2(theta)*sec^2(theta) - cot^2(theta) = csc^2(theta) - cot^2(theta) = 1}}}, or 

{{{cot^2(theta)*(sec^2(theta) - 1) = cot^2(theta)*tan^2(theta) = 1}}}