Infinite Limits — Question 9

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Question 9

Evaluate the limit: limx→0−2x+1x\lim_{x \to 0^-} \frac{2x + 1}{x}

Original worksheet page 1: question and worked solution for 2-6-009
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Question 9 - Solution

We are asked to evaluate: limx→0−2x+1x\lim_{x \to 0^-} \frac{2x + 1}{x}

Step 1: Behavior near zero from the left

As x→0−x \to 0^-, the numerator 2x+1→12x + 1 \to 1, since 2x→0−2x \to 0^- and 11 is a constant.

The denominator x→0−x \to 0^-, which is a small negative number.

So the entire fraction behaves like: 2x+1x≈1tiny negative=−∞\frac{2x + 1}{x} \approx \frac{1}{\text{tiny negative}} = -\infty

Step 2: More formal analysis (optional)

We can write: 2x+1x=2+1x\frac{2x + 1}{x} = 2 + \frac{1}{x}

As x→0−x \to 0^-, 1x→−∞\frac{1}{x} \to -\infty, and the constant 2 becomes negligible in comparison.

Conclusion: limx→0−2x+1x=−∞\boxed{\lim_{x \to 0^-} \frac{2x + 1}{x} = -\infty}

Original worksheet page 2: question and worked solution for 2-6-009

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