Simplify using fundamental identities

We know that $\sin^2 \theta + \cos^2 \theta = 1$ and $\sec^2 \theta - \tan^2 \theta = 1$. Substituting these into the original expression.

$1 - 1 + \cot \theta \sin \theta + \cos \theta$

Convert cotangent to sine and cosine

Substitute $\cot \theta = \frac{\cos \theta}{\sin \theta}$ into the expression and simplify the product.

$0 + \left(\frac{\cos \theta}{\sin \theta}\right) \sin \theta + \cos \theta$

Final addition

Canceling $\sin \theta$ in the term, we get $\cos \theta + \cos \theta = 2 \cos \theta$.

$2 \cos \theta$