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(i) int sec x dx=|log| tanx|+c (ii) in...

(i) `int sec x dx=|log| tanx|+c`
(ii) `int sec dx=log |secx+tanx|+c`

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The correct Answer is:
To solve the integrals given in the question, we will derive the integration of sec x step by step. ### Step-by-Step Solution 1. **Start with the integral of sec x:** \[ \int \sec x \, dx \] 2. **Multiply the integrand by a clever form of 1:** We can multiply the numerator and the denominator by \(\sec x + \tan x\): \[ \int \sec x \, dx = \int \frac{\sec x (\sec x + \tan x)}{\sec x + \tan x} \, dx \] 3. **Rewrite the integral:** This gives us: \[ \int \frac{\sec^2 x + \sec x \tan x}{\sec x + \tan x} \, dx \] 4. **Substitute \(u = \sec x + \tan x\):** Now, let: \[ u = \sec x + \tan x \] Then, we need to find \(du\): \[ du = (\sec x \tan x + \sec^2 x) \, dx \] 5. **Express dx in terms of du:** Rearranging gives: \[ dx = \frac{du}{\sec x \tan x + \sec^2 x} \] 6. **Substituting back into the integral:** The integral now becomes: \[ \int \frac{du}{u} \] 7. **Integrate:** The integral of \(\frac{1}{u}\) is: \[ \log |u| + C \] 8. **Substituting back for u:** Replace \(u\) with \(\sec x + \tan x\): \[ \int \sec x \, dx = \log |\sec x + \tan x| + C \] ### Conclusion Thus, the correct integral is: \[ \int \sec x \, dx = \log |\sec x + \tan x| + C \] ### Verification of the Given Options - (i) \(\int \sec x \, dx = | \log | \tan x | + C\) is **false**. - (ii) \(\int \sec x \, dx = \log |\sec x + \tan x| + C\) is **true**.
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