BrightChamps Logo
Login
Creative Math Ideas Image
Live Math Learners Count Icon103 Learners

Last updated on July 15th, 2025

Math Whiteboard Illustration

Derivative of sin²x

Professor Greenline Explaining Math Concepts

We use the derivative of sin²(x), which involves the chain rule, as a tool for understanding how the function changes in response to a slight change in x. Derivatives help us calculate profit or loss in real-life situations. We will now talk about the derivative of sin²(x) in detail.

Derivative of sin²x for UK Students
Professor Greenline from BrightChamps

What is the Derivative of sin²x?

We now understand the derivative of sin²x. It is commonly represented as d/dx (sin²x) or (sin²x)', and its value is 2sin(x)cos(x) or sin(2x). The function sin²x has a clearly defined derivative, indicating it is differentiable within its domain. The key concepts are mentioned below: - Sine Function: (sin(x) is a trigonometric function). - Chain Rule: Used for differentiating composite functions like sin²(x). - Double Angle Formula: sin(2x) = 2sin(x)cos(x).

Professor Greenline from BrightChamps

Derivative of sin²x Formula

The derivative of sin²x can be denoted as d/dx (sin²x) or (sin²x)'. The formula we use to differentiate sin²x is: d/dx (sin²x) = 2sin(x)cos(x) or (sin²x)' = sin(2x) The formula applies to all x where the sine function is defined.

Professor Greenline from BrightChamps

Proofs of the Derivative of sin²x

We can derive the derivative of sin²x using proofs. To show this, we will use trigonometric identities along with the rules of differentiation. There are several methods we use to prove this, such as: - By Chain Rule - Using Product Rule We will now demonstrate that the differentiation of sin²x results in 2sin(x)cos(x) using the above-mentioned methods: Using Chain Rule To prove the differentiation of sin²x using the chain rule, Consider y = (sin(x))² Let u = sin(x), then y = u² By the chain rule: dy/dx = 2u du/dx Since du/dx = cos(x), dy/dx = 2sin(x)cos(x) Using the double angle formula, sin(2x) = 2sin(x)cos(x), we have: dy/dx = sin(2x) Hence, proved. Using Product Rule We will now prove the derivative of sin²x using the product rule. The step-by-step process is demonstrated below: Here, we use the formula, sin²x = sin(x)·sin(x) Let u = sin(x) and v = sin(x) Using the product rule formula: d/dx [u·v] = u'·v + u·v' u' = d/dx (sin x) = cos x v' = d/dx (sin x) = cos x d/dx (sin²x) = cos(x)·sin(x) + sin(x)·cos(x) = 2sin(x)cos(x) Thus, d/dx (sin²x) = sin(2x) Hence, proved.

Professor Greenline from BrightChamps

Higher-Order Derivatives of sin²x

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 sin²(x). 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 sin²(x), we generally use fⁿ(x) for the nth derivative of a function f(x), which tells us the change in the rate of change.

Professor Greenline from BrightChamps

Special Cases:

- When x is 0, the derivative of sin²x = sin(2·0) = 0. - When x is π/4, the derivative of sin²x = sin(π/2) = 1.

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in Derivatives of sin²x

Students frequently make mistakes when differentiating sin²x. These mistakes can be resolved by understanding the proper solutions. Here are a few common mistakes and ways to solve them:

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Not simplifying the equation

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Students may forget to simplify the equation, which can lead to incomplete or incorrect results. They often skip steps and directly arrive at the result, especially when solving using the product or chain rule. Ensure that each step is written in order. Students might think it is awkward, but it is important to avoid errors in the process.

Mistake 2

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Forgetting the Double Angle Formula

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

They might not remember that sin²x can be expressed as sin(2x)/2. Keep in mind that using trigonometric identities like the double angle formula can simplify the differentiation process.

Mistake 3

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Incorrect use of Chain Rule

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

While differentiating functions such as sin²(2x), students misapply the chain rule. For example: Incorrect differentiation: d/dx (sin²(2x)) = 2sin(2x)cos(2x). To avoid this mistake, break it down: Let u = 2x, then differentiate using the chain rule: d/dx (sin²(u)) = 2sin(u)cos(u)·du/dx.

Mistake 4

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Not writing Constants and Coefficients

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

There is a common mistake that students at times forget to multiply the constants placed before sin²x. For example, they incorrectly write d/dx (3sin²x) = sin(2x). Students should check the constants in the terms and ensure they are multiplied properly. For e.g., the correct equation is d/dx (3sin²x) = 3sin(2x).

Mistake 5

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Not Applying the Product Rule

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Students often forget to use the product rule when necessary. This happens when the derivative of a product of functions is not considered. For example: Incorrect: d/dx (sin(x)sin(x)) = cos(x)cos(x). To fix this error, students should apply the product rule: d/dx (sin(x)sin(x)) = sin(x)cos(x) + cos(x)sin(x).

arrow-right
Max from BrightChamps Saying "Hey"

Examples Using the Derivative of sin²x

Ray, the Character from BrightChamps Explaining Math Concepts
Max, the Girl Character from BrightChamps

Problem 1

Calculate the derivative of (sin²x·cos(x))

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

Here, we have f(x) = sin²x·cos(x). Using the product rule, f'(x) = u′v + uv′ In the given equation, u = sin²x and v = cos(x). Let’s differentiate each term, u′ = d/dx (sin²x) = 2sin(x)cos(x) v′ = d/dx (cos(x)) = -sin(x) Substituting into the given equation, f'(x) = (2sin(x)cos(x))·(cos(x)) + (sin²x)·(-sin(x)) = 2sin(x)cos²(x) - sin³(x) Thus, the derivative of the specified function is 2sin(x)cos²(x) - sin³(x).

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.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 2

A company uses a solar panel to measure sunlight intensity, represented by the function y = sin²(x), where y represents the intensity at angle x. If x = π/6 radians, measure the rate of change of sunlight intensity.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

We have y = sin²(x) (intensity of sunlight)...(1) Now, we will differentiate the equation (1) Take the derivative of sin²(x): dy/dx = sin(2x) Given x = π/6 (substitute this into the derivative) sin(2x) = sin(2·π/6) = sin(π/3) = √3/2 Hence, the rate of change of sunlight intensity at x = π/6 is √3/2.

Explanation

We find the rate of change of sunlight intensity at x = π/6 as √3/2, which indicates how rapidly the intensity changes at that angle.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 3

Derive the second derivative of the function y = sin²(x).

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

The first step is to find the first derivative, dy/dx = sin(2x)...(1) Now we will differentiate equation (1) to get the second derivative: d²y/dx² = d/dx [sin(2x)] d²y/dx² = 2cos(2x) Therefore, the second derivative of the function y = sin²(x) is 2cos(2x).

Explanation

We use the step-by-step process, where we start with the first derivative. Using the chain rule, we differentiate sin(2x). We then substitute the identity and simplify the terms to find the final answer.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 4

Prove: d/dx (sin²(3x)) = 6sin(3x)cos(3x).

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

Let’s start using the chain rule: Consider y = sin²(3x) = [sin(3x)]² To differentiate, we use the chain rule: dy/dx = 2sin(3x) d/dx [sin(3x)] Since the derivative of sin(3x) is 3cos(3x), dy/dx = 2sin(3x)·3cos(3x) = 6sin(3x)cos(3x) Hence proved.

Explanation

In this step-by-step process, we used the chain rule to differentiate the equation. Then, we replace sin(3x) with its derivative. As a final step, we substitute y = sin²(3x) to derive the equation.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 5

Solve: d/dx (sin²x/x)

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

To differentiate the function, we use the quotient rule: d/dx (sin²x/x) = (d/dx (sin²x)·x - sin²x·d/dx(x))/x² We will substitute d/dx (sin²x) = 2sin(x)cos(x) and d/dx (x) = 1 = (2sin(x)cos(x)·x - sin²x·1) / x² = (2xsin(x)cos(x) - sin²x) / x² Therefore, d/dx (sin²x/x) = (2xsin(x)cos(x) - sin²x) / x²

Explanation

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

Max from BrightChamps Praising Clear Math Explanations
Ray Thinking Deeply About Math Problems

FAQs on the Derivative of sin²x

1.Find the derivative of sin²x.

Math FAQ Answers Dropdown Arrow

2.Can we use the derivative of sin²x in real life?

Math FAQ Answers Dropdown Arrow

3.Is it possible to take the derivative of sin²x at the point where x = π/2?

Math FAQ Answers Dropdown Arrow

4.What rule is used to differentiate sin²x/x?

Math FAQ Answers Dropdown Arrow

5.Are the derivatives of sin²x and sin²⁻¹x the same?

Math FAQ Answers Dropdown Arrow

6.Can we find the derivative of the sin²x formula?

Math FAQ Answers Dropdown Arrow
Professor Greenline from BrightChamps

Important Glossaries for the Derivative of sin²x

Derivative: The derivative of a function indicates how the given function changes in response to a slight change in x. Sine Function: The sine function is one of the primary trigonometric functions, written as sin(x). Chain Rule: A differentiation rule used for composite functions. Double Angle Formula: A trigonometric identity used to express trigonometric functions of double angles, like sin(2x) = 2sin(x)cos(x). Quotient Rule: A rule for differentiating functions that are divided by one another.

Math Teacher Background Image
Math Teacher Image

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.

Max, the Girl Character from BrightChamps

Fun Fact

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

INDONESIA - Axa Tower 45th floor, JL prof. Dr Satrio Kav. 18, Kel. Karet Kuningan, Kec. Setiabudi, Kota Adm. Jakarta Selatan, Prov. DKI Jakarta
INDIA - H.No. 8-2-699/1, SyNo. 346, Rd No. 12, Banjara Hills, Hyderabad, Telangana - 500034
SINGAPORE - 60 Paya Lebar Road #05-16, Paya Lebar Square, Singapore (409051)
USA - 251, Little Falls Drive, Wilmington, Delaware 19808
VIETNAM (Office 1) - Hung Vuong Building, 670 Ba Thang Hai, ward 14, district 10, Ho Chi Minh City
VIETNAM (Office 2) - 143 Nguyễn Thị Thập, Khu đô thị Him Lam, Quận 7, Thành phố Hồ Chí Minh 700000, Vietnam
Dubai - BrightChamps, 8W building 5th Floor, DAFZ, Dubai, United Arab Emirates
UK - Ground floor, Redwood House, Brotherswood Court, Almondsbury Business Park, Bristol, BS32 4QW, United Kingdom