Finding the Derivative of sin(x)cos(x)

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In summary, the derivative of sin(x)cos(x) is equal to cos^2(x) - sin^2(x) or cos(2x). It can be found using the product rule of derivatives and has significance in calculus and physics for analyzing the rate of change of a function. The derivative can be simplified further to cos(2x) using double angle formulas, and there are other methods such as the quotient rule and chain rule, but the product rule is the most efficient.
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Homework Statement



partial derivative (d/dx) sin(x)cos(x)

Homework Equations



Partial Derivatives, product rule

The Attempt at a Solution



sin(2x) = 2 sin x cos x, therefore y=sin(2x)/2

so y'=cos(2x)*(2/2) = cos (2x)?

Is this correct?
Is there an easier way of directly finding the derivative without using substitution?
 
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  • #2


I don't see why you would be using partial differentiation with this problem? It is not a product of two variables?

No, that's the quickest method. Use the trig identity to avoid product rule.

Either way, GOOD JOB!
 
Last edited:

1. What is the derivative of sin(x)cos(x)?

The derivative of sin(x)cos(x) is cos^2(x) - sin^2(x). This can also be written as cos(2x).

2. How do you find the derivative of sin(x)cos(x)?

To find the derivative of sin(x)cos(x), you can use the product rule of derivatives. This rule states that the derivative of two functions multiplied together is equal to the first function multiplied by the derivative of the second function, plus the second function multiplied by the derivative of the first function. In this case, the derivative is sin(x)*(-sin(x)) + cos(x)*(cos(x)), which simplifies to cos^2(x) - sin^2(x).

3. What is the significance of finding the derivative of sin(x)cos(x)?

Finding the derivative of sin(x)cos(x) is important in calculus and physics, as it allows us to analyze and understand the rate of change of a function. It can also be used to solve various problems involving motion, such as finding the velocity or acceleration of an object.

4. Can the derivative of sin(x)cos(x) be simplified further?

Yes, the derivative of sin(x)cos(x) can be simplified to cos(2x). This is a trigonometric identity that can be derived using double angle formulas.

5. Are there any other ways to find the derivative of sin(x)cos(x)?

Yes, you can also use the quotient rule and chain rule to find the derivative of sin(x)cos(x). However, the product rule is the most efficient method in this case.

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