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Last updated on 2 September 2025

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Derivative of -e^x

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We explore the derivative of -e^x, which is -e^x itself, as a tool to understand how the function changes in response to a slight change in x. Derivatives are crucial in real-life situations for calculating factors like profit or loss. We will now delve into the derivative of -e^x in detail.

Derivative of -e^x for UK Students
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What is the Derivative of -e^x?

We now understand the derivative of -ex.

It is commonly represented as d/dx(-ex) or (-ex)', and its value is -ex.

The function -ex has a clearly defined derivative, indicating it is differentiable across its domain.

The key concepts are mentioned below:

Exponential Function: (-ex is an exponential function).

Derivative of e^x: The derivative of ex is ex.

Negative Constant Multiplier Rule: The derivative of a constant times a function is the constant times the derivative of the function.

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Derivative of -e^x Formula

The derivative of -ex can be denoted as d/dx(-ex) or (-ex)'. The formula we use to differentiate -ex is: d/dx(-ex) = -ex (or) (-ex)' = -ex This formula applies to all x in the domain of real numbers.

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Proofs of the Derivative of -e^x

We can derive the derivative of -ex using proofs.

To show this, we will use the properties of exponential functions along with the basic rules of differentiation. There are several methods we use to prove this, such as:

 

By First Principle Using Constant Multiplier Rule

We will now demonstrate that the differentiation of -ex results in -e^x using the above-mentioned methods:

By First Principle The derivative of -ex can be proved using the First Principle, which expresses the derivative as the limit of the difference quotient.

To find the derivative of -e^x using the first principle, we will consider f(x) = -ex.

Its derivative can be expressed as the following limit. f'(x) = limₕ→₀ [f(x + h) - f(x)] / h

Given that f(x) = -ex, we write f(x + h) = -e(x + h).

Substituting these into the equation, f'(x) = limₕ→₀ [-e^(x + h) + e^x] / h = limₕ→₀ [-ex * (eh - 1)] / h

Using the limit properties, limₕ→₀ (eh - 1)/h = 1, f'(x) = -ex * 1 = -ex.

Hence, proved.

 

Using Constant Multiplier Rule

To prove the differentiation of -ex using the constant multiplier rule, We use the formula:

The derivative of a constant times a function is the constant times the derivative of the function.

Let u(x) = ex, so -ex = -1 * u(x).

By the constant multiplier rule: d/dx(-1 * u(x)) = -1 * d/dx(u(x)) Since d/dx(ex) = ex, we have: d/dx(-ex) = -1 * ex = -ex. Thus, the derivative is -ex.

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Higher-Order Derivatives of -e^x

When a function is differentiated several times, the derivatives obtained are referred to as higher-order derivatives. Higher-order derivatives can be a little tricky.

To understand them better, think of a car where the speed changes (first derivative) and the rate at which the speed changes (second derivative) also changes.

Higher-order derivatives make it easier to understand functions like -ex.

For the first derivative of a function, we write f′(x), which indicates how the function changes or its slope at a certain point.

The second derivative is derived from the first derivative, which is denoted using f′′(x).

Similarly, the third derivative, f′′′(x) is the result of the second derivative, and this pattern continues.

For the nth Derivative of -ex, we generally use fⁿ(x) for the nth derivative of a function f(x), which tells us the change in the rate of change. (continuing for higher-order derivatives).

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Special Cases:

The exponential function -ex is defined for all real x, hence it does not have any undefined points in its domain. When x is 0, the derivative of -ex is -1, since -e0 = -1.

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Common Mistakes and How to Avoid Them in Derivatives of -e^x

Students frequently make mistakes when differentiating -ex. These mistakes can be resolved by understanding the proper solutions. Here are a few common mistakes and ways to solve them:

Mistake 1

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Not applying the negative sign

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Students may forget to apply the negative sign in front of the derivative of ex, which can lead to incorrect results. Always remember that the derivative of -ex is -ex, not ex.

Mistake 2

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Confusing with other exponential functions

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Students might confuse the derivative of -ex with that of other exponential functions like ex or ax. Keep in mind that each exponential function has its specific derivative formula.

Mistake 3

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Incorrect use of the chain rule

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While differentiating composite functions involving -ex, students may misapply the chain rule.

 

For example, in d/dx(-e(2x)), students might incorrectly write the derivative as -e(2x) instead of -2e(2x). Always apply the chain rule correctly by differentiating the exponent as well.

Mistake 4

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Ignoring the constant multiplier rule

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There is a common mistake where students ignore the constant multiplier rule when differentiating -ex. They might forget to multiply the negative sign through the differentiation process. Always apply the constant multiplier rule correctly.

Mistake 5

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Confusing the derivative of ex with that of e-x

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Students often confuse the derivative of ex with the derivative of e-x. Remember that d/dx(ex) = ex and d/dx(-ex) = -ex.

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Examples Using the Derivative of -e^x

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Problem 1

Calculate the derivative of (-e^x * e^x)

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Here, we have f(x) = -ex * ex.

Using the product rule, f'(x) = u′v + uv′ In the given equation, u = -ex and v = ex.

Let’s differentiate each term, u′= d/dx(-ex) = -ex v′= d/dx(ex) = ex

Substituting into the given equation, f'(x) = (-ex) * ex + (-ex) * ex

Let’s simplify terms to get the final answer, f'(x) = -2e(2x)

Thus, the derivative of the specified function is -2e(2x).

Explanation

We find the derivative of the given function by dividing the function into two parts. The first step is finding its derivative and then combining them using the product rule to get the final result.

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Problem 2

A company experiences exponential decay in its product sales, represented by the function S(x) = -e^x. Measure the rate of decay when x = 1.

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We have S(x) = -ex (rate of decay)...

Now, we will differentiate the equation.

Take the derivative of -ex: dS/dx = -ex

Given x = 1 (substitute this into the derivative), dS/dx = -e1 = -e

Hence, the rate of decay of sales when x = 1 is -e.

Explanation

We find the rate of decay of sales at x = 1 as -e, which indicates the decay rate is the negative exponential of 1 at that point.

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Problem 3

Derive the second derivative of the function y = -e^x.

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The first step is to find the first derivative, dy/dx = -ex...

Now we will differentiate the equation to get the second derivative: d²y/dx² = d/dx[-ex]

Since d/dx(-ex) = -ex, d²y/dx² = -ex

Therefore, the second derivative of the function y = -ex is -ex.

Explanation

We use the step-by-step process, starting with the first derivative. The second derivative is simply the first derivative of the first derivative for this function, resulting in the same form as the original function.

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Problem 4

Prove: d/dx((-e^x)²) = -2e^(2x).

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Let’s start using the chain rule:

Consider y = (-ex)² = [(-ex)]²

To differentiate, we use the chain rule: dy/dx = 2(-ex) * d/dx(-ex)

Since the derivative of -ex is -ex, dy/dx = 2(-ex) * (-ex) = -2e(2x)

Hence proved.

Explanation

In this step-by-step process, we used the chain rule to differentiate the equation. We then replace -ex with its derivative. As a final step, we simplify to derive the equation.

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Problem 5

Solve: d/dx(-e^x/x)

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To differentiate the function, we use the quotient rule: d/dx(-e^x/x) = (d/dx(-ex) * x - (-ex) * d/dx(x))/x²

We will substitute d/dx(-ex) = -ex and d/dx(x) = 1 = (-ex * x + ex * 1)/x² = (-xex + ex)/x² = -ex(x - 1)/x²

Therefore, d/dx(-ex/x) = -ex(x - 1)/x²

Explanation

In this process, we differentiate the given function using the quotient rule. As a final step, we simplify the equation to obtain the final result.

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FAQs on the Derivative of -e^x

1.Find the derivative of -e^x.

The derivative of -ex is -ex, as it is an exponential function with a negative coefficient.

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2.Can we use the derivative of -e^x in real life?

Yes, we can use the derivative of -ex in real life to model exponential decay processes, such as radioactive decay or population decline.

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3.Is the derivative of -e^x undefined at any point?

No, the derivative of -ex is defined for all real numbers, as the exponential function is continuous everywhere.

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4.What rule is used to differentiate -e^x/x?

We use the quotient rule to differentiate -ex/x, d/dx(-ex/x) = (-ex * x + ex)/x².

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5.Are the derivatives of e^x and -e^x the same?

No, they are different. The derivative of ex is ex, while the derivative of -ex is -ex.

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6.Can we find the derivative of the -e^x formula?

Yes, to find it, we use the fact that -ex is an exponential function with a constant multiplier: d/dx(-ex) = -1 * d/dx(ex) = -ex.

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Important Glossaries for the Derivative of -e^x

  • Derivative: The derivative of a function indicates how the given function changes in response to a slight change in x.

 

  • Exponential Function: A mathematical function of the form a^x, where a is a constant. -ex is a specific exponential function.

 

  • First Derivative: The initial result of differentiating a function, showing the rate of change of the function.

 

  • Constant Multiplier Rule: A rule stating that the derivative of a constant times a function is the constant times the derivative of the function.

 

  • Quotient Rule: A rule used to differentiate functions that are the ratio of two differentiable functions.
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Jaskaran Singh Saluja

About the Author

Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.

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Fun Fact

: He loves to play the quiz with kids through algebra to make kids love it.

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