23 March 2020 Sergiu Funieru The formula for cot (-a) [formula for the cotangent of minus a] 0 The formula for cot (-a) [formula for the cotangent of minus a] Have you seen this? 0
![The formula for cot (-a) [formula for the cotangent of minus a]](https://lunlun.com/wp-content/uploads/2020/03/The-formula-for-cot-a-formula-for-the-cotangent-of-minus-a.png "The formula for cot (-a) [formula for the cotangent of minus a]")