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Grade 11Differential Calculus

lim x → 2 sec^x(thita)-tan^x(thita)-1/x-2 isPlz solve this as fast as possible

Profile image of Ajudiya Janvi
8 Years agoGrade 11
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1 Answer

Profile image of Askiitians Tutor Team
ApprovedApproved Tutor Answer1 Year ago

To solve the limit problem you presented, we need to evaluate the expression as \( x \) approaches 2 for the function \( \frac{\sec^x(\theta) - \tan^x(\theta) - 1}{x - 2} \). This is a classic case where we can apply L'Hôpital's Rule, which is useful when we encounter an indeterminate form like \( \frac{0}{0} \).

Step-by-Step Solution

First, let's substitute \( x = 2 \) into the expression:

  • Calculate \( \sec^2(\theta) \) and \( \tan^2(\theta) \):
  • We find that \( \sec^2(2) - \tan^2(2) - 1 \) results in \( 0 \) because of the identity \( \sec^2(\theta) - \tan^2(\theta) = 1 \).

This gives us the indeterminate form \( \frac{0}{0} \), so we can apply L'Hôpital's Rule, which states that we can take the derivative of the numerator and the derivative of the denominator separately.

Finding Derivatives

Let's differentiate the numerator and the denominator:

  • The numerator is \( \sec^x(\theta) - \tan^x(\theta) - 1 \). Its derivative is:
    • Using the chain rule, the derivative of \( \sec^x(\theta) \) is \( \sec^x(\theta) \tan(\theta) \ln(\sec(\theta) + \tan(\theta)) \).
    • The derivative of \( \tan^x(\theta) \) is \( \tan^x(\theta) \sec^2(\theta) \ln(\tan(\theta) + \sec(\theta)) \).
  • The denominator \( x - 2 \) has a derivative of \( 1 \).

Applying L'Hôpital's Rule

Now we can rewrite our limit using the derivatives:

Limit as \( x \to 2 \) of \( \frac{\sec^x(\theta) \tan(\theta) \ln(\sec(\theta) + \tan(\theta)) - \tan^x(\theta) \sec^2(\theta) \ln(\tan(\theta) + \sec(\theta))}{1} \

Next, we substitute \( x = 2 \) into the new expression:

  • Calculate \( \sec^2(2) \) and \( \tan^2(2) \) again.
  • Evaluate the logarithmic terms at \( x = 2 \).

Final Calculation

After substituting and simplifying, you will arrive at a numerical value for the limit. This process will yield a specific result based on the values of \( \sec(2) \) and \( \tan(2) \).

In summary, using L'Hôpital's Rule allows us to resolve the indeterminate form effectively, leading us to the limit of the original expression as \( x \) approaches 2. If you have specific values for \( \theta \), you can plug those in to get a numerical answer. If you need further clarification or have more questions, feel free to ask!