How to use trig identities to divide two trig functions

The video tutorial explains the concept of dividing by fractions using reciprocals, highlighting that dividing a number by itself results in one. It introduces the cofunction identity involving tangent and cotangent, and discusses the property of cotangent with negative angles. The tutorial concludes with a brief mention of corrections to earlier mistakes.

Explain the significance of the negative angle in the context of cotangent as discussed by the teacher.

What mistake did the teacher acknowledge making during the explanation?