I'm trying to solve: $$\cot\frac{\pi}{12}$$
Given: $$\cot(\theta-\phi)=\frac{\cot\theta \cot\phi+1}{\cot\theta-\cot\phi}$$
And: $$\cot\frac{\pi}{3}=\frac{1}{\sqrt{3}};\cot\frac{\pi}{4}=1$$
$$\frac{\frac{1}{\sqrt{3}}(1)+1}{\frac{1}{\sqrt{3}}-1}$$ $$\frac{1+\sqrt{3}}{1-\sqrt{3}}$$
The answer should be: $3.732(4sf)$ but I keep getting: $-3.732(4sf)$
Where am I going wrong?
Is it because: $\cot\theta = -\cot\theta$ ?