Calculus Examples

$lim_{x \to 0} {(1 - 2 x)}^{\frac{1}{x}}$

Step 1

Use the properties of logarithms to simplify the limit.

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Step 1.1

Rewrite ${(1 - 2 x)}^{\frac{1}{x}}$ as $e^{\ln ({(1 - 2 x)}^{\frac{1}{x}})}$ .

$lim_{x \to 0} e^{\ln ({(1 - 2 x)}^{\frac{1}{x}})}$

Step 1.2

Expand $\ln ({(1 - 2 x)}^{\frac{1}{x}})$ by moving $\frac{1}{x}$ outside the logarithm.

$lim_{x \to 0} e^{\frac{1}{x} \ln (1 - 2 x)}$

Step 2

Evaluate the limit.

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Step 2.1

Move the limit into the exponent.

$e^{lim_{x \to 0} \frac{1}{x} \ln (1 - 2 x)}$

Step 2.2

Combine $\frac{1}{x}$ and $\ln (1 - 2 x)$ .

$e^{lim_{x \to 0} \frac{\ln (1 - 2 x)}{x}}$

Step 3

Apply L'Hospital's rule.

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Step 3.1

Evaluate the limit of the numerator and the limit of the denominator.

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Step 3.1.1

Take the limit of the numerator and the limit of the denominator.

$e^{\frac{lim_{x \to 0} \ln (1 - 2 x)}{lim_{x \to 0} x}}$

Step 3.1.2

Evaluate the limit of the numerator.

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Step 3.1.2.1

Evaluate the limit.

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Step 3.1.2.1.1

Move the limit inside the logarithm.

$e^{\frac{\ln (lim_{x \to 0} 1 - 2 x)}{lim_{x \to 0} x}}$

Step 3.1.2.1.2

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $0$ .

$e^{\frac{\ln (lim_{x \to 0} 1 - lim_{x \to 0} 2 x)}{lim_{x \to 0} x}}$

Step 3.1.2.1.3

Evaluate the limit of $1$ which is constant as $x$ approaches $0$ .

$e^{\frac{\ln (1 - lim_{x \to 0} 2 x)}{lim_{x \to 0} x}}$

Step 3.1.2.1.4

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$e^{\frac{\ln (1 - 2 lim_{x \to 0} x)}{lim_{x \to 0} x}}$

Step 3.1.2.2

Evaluate the limit of $x$ by plugging in $0$ for $x$ .

$e^{\frac{\ln (1 - 2 \cdot 0)}{lim_{x \to 0} x}}$

Step 3.1.2.3

Simplify the answer.

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Step 3.1.2.3.1

Multiply $- 2$ by $0$ .

$e^{\frac{\ln (1 + 0)}{lim_{x \to 0} x}}$

Step 3.1.2.3.2

Add $1$ and $0$ .

$e^{\frac{\ln (1)}{lim_{x \to 0} x}}$

Step 3.1.2.3.3

The natural logarithm of $1$ is $0$ .

$e^{\frac{0}{lim_{x \to 0} x}}$

Step 3.1.3

Evaluate the limit of $x$ by plugging in $0$ for $x$ .

$e^{\frac{0}{0}}$

Step 3.1.4

The expression contains a division by $0$ . The expression is undefined.

Undefined

$e^{\frac{0}{0}}$

Step 3.2

Since $\frac{0}{0}$ is of indeterminate form, apply L'Hospital's Rule. L'Hospital's Rule states that the limit of a quotient of functions is equal to the limit of the quotient of their derivatives.

$lim_{x \to 0} \frac{\ln (1 - 2 x)}{x} = lim_{x \to 0} \frac{\frac{d}{d x} [\ln (1 - 2 x)]}{\frac{d}{d x} [x]}$

Step 3.3

Find the derivative of the numerator and denominator.

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Step 3.3.1

Differentiate the numerator and denominator.

$e^{lim_{x \to 0} \frac{\frac{d}{d x} [\ln (1 - 2 x)]}{\frac{d}{d x} [x]}}$

Step 3.3.2

Differentiate using the chain rule, which states that $\frac{d}{d x} [f (g (x))]$ is $f' (g (x)) g' (x)$ where $f (x) = \ln (x)$ and $g (x) = 1 - 2 x$ .

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Step 3.3.2.1

To apply the Chain Rule, set $u$ as $1 - 2 x$ .

$e^{lim_{x \to 0} \frac{\frac{d}{d u} [\ln (u)] \frac{d}{d x} [1 - 2 x]}{\frac{d}{d x} [x]}}$

Step 3.3.2.2

The derivative of $\ln (u)$ with respect to $u$ is $\frac{1}{u}$ .

$e^{lim_{x \to 0} \frac{\frac{1}{u} \frac{d}{d x} [1 - 2 x]}{\frac{d}{d x} [x]}}$

Step 3.3.2.3

Replace all occurrences of $u$ with $1 - 2 x$ .

$e^{lim_{x \to 0} \frac{\frac{1}{1 - 2 x} \frac{d}{d x} [1 - 2 x]}{\frac{d}{d x} [x]}}$

Step 3.3.3

By the Sum Rule, the derivative of $1 - 2 x$ with respect to $x$ is $\frac{d}{d x} [1] + \frac{d}{d x} [- 2 x]$ .

$e^{lim_{x \to 0} \frac{\frac{1}{1 - 2 x} (\frac{d}{d x} [1] + \frac{d}{d x} [- 2 x])}{\frac{d}{d x} [x]}}$

Step 3.3.4

Since $1$ is constant with respect to $x$ , the derivative of $1$ with respect to $x$ is $0$ .

$e^{lim_{x \to 0} \frac{\frac{1}{1 - 2 x} (0 + \frac{d}{d x} [- 2 x])}{\frac{d}{d x} [x]}}$

Step 3.3.5

Add $0$ and $\frac{d}{d x} [- 2 x]$ .

$e^{lim_{x \to 0} \frac{\frac{1}{1 - 2 x} \frac{d}{d x} [- 2 x]}{\frac{d}{d x} [x]}}$

Step 3.3.6

Since $- 2$ is constant with respect to $x$ , the derivative of $- 2 x$ with respect to $x$ is $- 2 \frac{d}{d x} [x]$ .

$e^{lim_{x \to 0} \frac{\frac{1}{1 - 2 x} \cdot - 2 \frac{d}{d x} [x]}{\frac{d}{d x} [x]}}$

Step 3.3.7

Combine $- 2$ and $\frac{1}{1 - 2 x}$ .

$e^{lim_{x \to 0} \frac{\frac{- 2}{1 - 2 x} \frac{d}{d x} [x]}{\frac{d}{d x} [x]}}$

Step 3.3.8

Move the negative in front of the fraction.

$e^{lim_{x \to 0} \frac{- \frac{2}{1 - 2 x} \frac{d}{d x} [x]}{\frac{d}{d x} [x]}}$

Step 3.3.9

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$e^{lim_{x \to 0} \frac{- \frac{2}{1 - 2 x} \cdot 1}{\frac{d}{d x} [x]}}$

Step 3.3.10

Multiply $- 1$ by $1$ .

$e^{lim_{x \to 0} \frac{- \frac{2}{1 - 2 x}}{\frac{d}{d x} [x]}}$

Step 3.3.11

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$e^{lim_{x \to 0} \frac{- \frac{2}{1 - 2 x}}{1}}$

Step 3.4

Multiply the numerator by the reciprocal of the denominator.

$e^{lim_{x \to 0} - \frac{2}{1 - 2 x} \cdot 1}$

Step 3.5

Multiply $- 1$ by $1$ .

$e^{lim_{x \to 0} - \frac{2}{1 - 2 x}}$

Step 4

Evaluate the limit.

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Step 4.1

Move the term $- 1$ outside of the limit because it is constant with respect to $x$ .

$e^{- lim_{x \to 0} \frac{2}{1 - 2 x}}$

Step 4.2

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$e^{- 2 lim_{x \to 0} \frac{1}{1 - 2 x}}$

Step 4.3

Split the limit using the Limits Quotient Rule on the limit as $x$ approaches $0$ .

$e^{- 2 \frac{lim_{x \to 0} 1}{lim_{x \to 0} 1 - 2 x}}$

Step 4.4

Evaluate the limit of $1$ which is constant as $x$ approaches $0$ .

$e^{- 2 \frac{1}{lim_{x \to 0} 1 - 2 x}}$

Step 4.5

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $0$ .

$e^{- 2 \frac{1}{lim_{x \to 0} 1 - lim_{x \to 0} 2 x}}$

Step 4.6

Evaluate the limit of $1$ which is constant as $x$ approaches $0$ .

$e^{- 2 \frac{1}{1 - lim_{x \to 0} 2 x}}$

Step 4.7

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$e^{- 2 \frac{1}{1 - 2 lim_{x \to 0} x}}$

Step 5

Evaluate the limit of $x$ by plugging in $0$ for $x$ .

$e^{- 2 \frac{1}{1 - 2 \cdot 0}}$

Step 6

Simplify the answer.

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Step 6.1

Simplify the denominator.

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Step 6.1.1

Multiply $- 2$ by $0$ .

$e^{- 2 \frac{1}{1 + 0}}$

Step 6.1.2

Add $1$ and $0$ .

$e^{- 2 (\frac{1}{1})}$

Step 6.2

Cancel the common factor of $1$ .

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Step 6.2.1

Cancel the common factor.

$e^{- 2 (\frac{1}{1})}$

Step 6.2.2

Rewrite the expression.

$e^{- 2 \cdot 1}$

Step 6.3

Multiply $- 2$ by $1$ .

$e^{- 2}$

Step 6.4

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$\frac{1}{e^{2}}$

Step 7

The result can be shown in multiple forms.

Exact Form:

$\frac{1}{e^{2}}$

Decimal Form:

$0.13533528 \dots$