To solve the equation \( \tan x \cos x + \tan x = \cos x + 1 \), we can start by rewriting the equation using the identity for \(\tan x\):
\[ \tan x = \frac{\sin x}{\cos x} \]
Thus, we can substitute \(\tan x\) into the equation:
\[ \frac{\sin x}{\cos x} \cos x + \frac{\sin x}{\cos x} = \cos x + 1 \]
This simplifies to:
\[ \sin x + \frac{\sin x}{\cos x} = \cos x + 1 \]
We multiply through by \(\cos x\) (keeping in mind that \(\cos x \neq 0\)):
\[ \sin x \cos x + \sin x = \cos^2 x + \cos x \]
Now we can combine terms on the left-hand side:
\[ \sin x (\cos x + 1) = \cos^2 x + \cos x \]
Next, we can rearrange this:
\[ \sin x (\cos x + 1) - (\cos^2 x + \cos x) = 0 \]
Factoring out \(\cos x\) from the terms on the right, we obtain:
\[ \sin x (\cos x + 1) - \cos x(\cos x + 1) = 0 \]
Factoring the entire expression gives us:
\[ (\cos x + 1)(\sin x - \cos x) = 0 \]
This gives us two cases to solve:
- \( \cos x + 1 = 0 \)
- \( \sin x - \cos x = 0 \)
For the first case:
\[ \cos x + 1 = 0 \implies \cos x = -1 \]
This occurs at:
\[ x = \pi + 2k\pi \quad (k \in \mathbb{Z}) \]
For the second case:
\[ \sin x - \cos x = 0 \implies \sin x = \cos x \]
This happens when:
\[ \tan x = 1 \implies x = \frac{\pi}{4} + k\pi \quad (k \in \mathbb{Z}) \]
Thus, the complete solution set for the equation \( \tan x \cos x + \tan x = \cos x + 1 \) is:
\[ x = \pi + 2k\pi \quad (k \in \mathbb{Z}) \quad \text{and} \quad x = \frac{\pi}{4} + k\pi \quad (k \in \mathbb{Z}) \]