Math Problem Statement

Solve for the limit as x goes to 0 of sec(x)cot(x) analytically

Solution

We are asked to find the limit of the expression sec(x)cot(x)\sec(x) \cot(x) as xx approaches 0:

limx0sec(x)cot(x)\lim_{x \to 0} \sec(x) \cot(x)

Step 1: Rewrite sec(x)\sec(x) and cot(x)\cot(x) in terms of basic trigonometric functions

We know that:

  • sec(x)=1cos(x)\sec(x) = \frac{1}{\cos(x)}
  • cot(x)=cos(x)sin(x)\cot(x) = \frac{\cos(x)}{\sin(x)}

Substituting these into the expression, we get:

sec(x)cot(x)=1cos(x)cos(x)sin(x)=1sin(x)\sec(x) \cot(x) = \frac{1}{\cos(x)} \cdot \frac{\cos(x)}{\sin(x)} = \frac{1}{\sin(x)}

Step 2: Simplify the expression

Thus, the original expression reduces to:

1sin(x)\frac{1}{\sin(x)}

Step 3: Take the limit as x0x \to 0

We now need to find the limit:

limx01sin(x)\lim_{x \to 0} \frac{1}{\sin(x)}

Since sin(x)0\sin(x) \to 0 as x0x \to 0, the limit of 1sin(x)\frac{1}{\sin(x)} approaches \infty. Therefore:

limx01sin(x)=\lim_{x \to 0} \frac{1}{\sin(x)} = \infty

Conclusion:

The limit of sec(x)cot(x)\sec(x) \cot(x) as xx approaches 0 is \infty.

Would you like further details on this solution or have any questions?

Here are 5 related questions to consider:

  1. What is the limit of 1tan(x)\frac{1}{\tan(x)} as x0x \to 0?
  2. How does the behavior of trigonometric functions around 0 affect limits?
  3. What is the significance of limits approaching infinity in real-world scenarios?
  4. Can L'Hopital's Rule be applied to solve similar limits, and how?
  5. What are some common limits involving sec(x)\sec(x) and cot(x)\cot(x)?

Tip: When dealing with trigonometric limits, rewriting the functions in simpler terms (like sine and cosine) often makes the limit easier to compute.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Limits
Secant Function
Cotangent Function

Formulas

sec(x) = 1 / cos(x)
cot(x) = cos(x) / sin(x)
Limit of 1 / sin(x) as x -> 0

Theorems

Limit Theorems
Behavior of Trigonometric Functions Near Zero

Suitable Grade Level

Undergraduate Calculus