Let's re-evaluate the expression with the correct trigonometric values, considering the identity and standard values of $\tan 0$, $\csc 0$, $\sin 0$, and $\sec 0$.

The expression given is $\tan^2 \theta - \csc \theta + \sin \theta \sec \theta$.

However, we need to correct the initial problem as there is no angle $\theta$ for which $\tan \theta = 2$ when $\theta = 0$.

Let's re-evaluate it with correct trigonometric identities and standard values:

1. Correct $\tan^2 0$: $\tan 0 = 0 \implies \tan^2 0 = 0^2 = 0$

2. Correct $\csc 0$: $\csc 0 = \frac{1}{\sin 0}$ Since $\sin 0 = 0$, $\csc 0$ is undefined. But if we're simplifying for practical values and standard identities, we generally avoid division by zero.

3. Evaluate $\sin 0 \sec 0$: $\sec 0 = \frac{1}{\cos 0} = \frac{1}{1} = 1$ $\sin 0 \sec 0 = 0 \times 1 = 0$

So, assuming $\tan 0 = 2$ was a mistake (perhaps $\tan 0 = 0$ was intended), then the correct evaluation should be:

$\tan^2 0 - \csc 0 + \sin 0 \sec 0 = 0 - \text{undefined} + 0$

Thus, with corrected trigonometric identities:

• $\tan 0 = 0$
• $\sin 0 = 0$
• $\cos 0 = 1$
• $\sec 0 = 1$
• $\csc 0 = \text{undefined}$

The entire expression is undefined due to $\csc 0$.

For a clearer context, let's rephrase the problem with a valid angle where all trigonometric functions are defined.

Would you like any further details or have any questions?

Here are some questions you might want to ask:

1. How do you determine the correct values of trigonometric functions at specific angles?
2. What are some common mistakes to avoid in trigonometric calculations?
3. How do you work with undefined values in trigonometric functions?
4. What are the identities involving $\tan \theta$ and $\sec \theta$?
5. How can we use limits to handle undefined trigonometric expressions?

Tip: Always verify the domain and range of trigonometric functions to avoid undefined expressions and ensure accurate calculations.