Integral Tan Sec 404906
1. **State the problem:** We want to find the integral $$\int (\tan x + \sec x)^2 \, dx$$.
2. **Use the formula:** Expand the square using algebraic identity $$(a+b)^2 = a^2 + 2ab + b^2$$:
$$ (\tan x + \sec x)^2 = \tan^2 x + 2 \tan x \sec x + \sec^2 x $$
3. **Rewrite the integral:**
$$ \int (\tan^2 x + 2 \tan x \sec x + \sec^2 x) \, dx = \int \tan^2 x \, dx + 2 \int \tan x \sec x \, dx + \int \sec^2 x \, dx $$
4. **Recall important identities:**
- $\frac{d}{dx}(\tan x) = \sec^2 x$
- $\frac{d}{dx}(\sec x) = \sec x \tan x$
- $\tan^2 x = \sec^2 x - 1$
5. **Evaluate each integral:**
- $$\int \tan^2 x \, dx = \int (\sec^2 x - 1) \, dx = \int \sec^2 x \, dx - \int 1 \, dx = \tan x - x + C_1$$
- $$2 \int \tan x \sec x \, dx = 2 \int \sec x \tan x \, dx = 2 \sec x + C_2$$
- $$\int \sec^2 x \, dx = \tan x + C_3$$
6. **Combine all results:**
$$ \tan x - x + 2 \sec x + \tan x + C $$
7. **Simplify:**
$$ 2 \tan x + 2 \sec x - x + C $$
**Final answer:**
$$ \int (\tan x + \sec x)^2 \, dx = 2 \tan x + 2 \sec x - x + C $$