Why Is the Derivative of sin(ax²) Equal to 2axcos(ax²)?

In summary, the derivative of sin(ax²) is 2axcos(ax²) because of the chain rule, which states that the derivative of a composite function is equal to the derivative of the outer function evaluated at the inner function, multiplied by the derivative of the inner function. In this case, the outer function is sin(x) and the inner function is ax², which results in a derivative of 2axcos(ax²).
  • #1
wahaj
156
2
The derivative of sin(ax²) is 2axcos(ax²). Why is that? I understand the cos(ax²) part of the derivative but I don't understand where the 2ax is coming from.
 
Physics news on Phys.org
  • #2
Do you know the chain rule?
 
  • #3
wahaj said:
The derivative of sin(ax²) is 2axcos(ax²). Why is that? I understand the cos(ax²) part of the derivative but I don't understand where the 2ax is coming from.


You can google "Chain rule". It says that

$$\left(f(g(x)\right)'=f'(g(x))\cdot g'(x)$$

In the present case we have [itex]\,f(x)=\sin x\,\,\,,\,\,\,g(x)=ax^2\,[/itex]

DonAntonio
 
  • #4
that makes a lot more sense. thanks
 

FAQ: Why Is the Derivative of sin(ax²) Equal to 2axcos(ax²)?

What is a derivative?

A derivative is a mathematical concept that represents the rate of change of a function with respect to its input variable. It measures how much a function changes for a small change in its input value.

Why do we need derivatives?

Derivatives are essential in several areas of mathematics, physics, and engineering. They help us analyze and understand the behavior of functions, optimize functions to find maximum or minimum values, and solve problems involving rates of change.

How do you find the derivative of a function?

The process of finding the derivative of a function is called differentiation. It involves using specific rules and formulas, such as the power rule, product rule, and chain rule, to express the rate of change of a function in terms of its input variable.

What is the importance of derivatives in real-world applications?

Derivatives have numerous real-world applications, such as in physics (e.g., calculating velocity and acceleration), economics (e.g., finding marginal cost and revenue), and engineering (e.g., optimizing designs). They also play a crucial role in financial mathematics and data analysis.

Can you give an example of a real-life situation where derivatives are used?

One example is in the design of roller coasters. Engineers use derivatives to analyze the curves of a track and ensure a smooth and safe ride for passengers. They also use derivatives to calculate the speed, acceleration, and forces acting on the riders at different points of the ride.

Similar threads

Replies
8
Views
1K
Replies
4
Views
1K
Replies
5
Views
2K
Replies
5
Views
647
Replies
9
Views
2K
Back
Top