I found a proof for the vector chain rule, but it makese no sense to me

In summary, the conversation is about finding a proof for the vector chain rule. The speaker found one online, but is having trouble understanding it. They mention that it relies on mathematical intuition and familiarity with approximating things by Taylor series. The speaker also mentions that they are more familiar with a proof that involves limits and may need to find another proof to fully understand the concept.
  • #1
mr_coffee
1,629
1
Hello everyone, our professor wanted us to find the vector chain rule proof and i found one here:
http://web.mit.edu/wwmath/vectorc/scalar/chain.html
But it makes no sense to me, where are the limits?
 
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  • #2
Taking the limit is implied when the author says "Now as we let delta t go to zero". This kind of proof relies a bit more on mathematical intuition than the definition for the derivative you learn in Calc I. For one thing, it implies you're familiar with approximating things by Taylor series. Which part of the proof are you having trouble with?
 
  • #3
hah well i did take that in calc II but forgot even how that works, but i don't get how he starts off saying, let's first notice a few things... x(t+change in t) = x + chag in x
then he goes to say:
now by linear approximation...what the? is there another proof that goes through the limits, i understand that a lot better. He told us to find proofs and make sure we understand them, so he isn't grading this, but he will probably tell us to prove it on an exam
 

Related to I found a proof for the vector chain rule, but it makese no sense to me

What is the vector chain rule and why is it important in mathematics?

The vector chain rule is a fundamental concept in multivariable calculus that allows us to calculate the derivative of a function with respect to another variable. It is important because it is used in many areas of mathematics and science, such as in physics and engineering, to model and understand complex systems.

How does the vector chain rule differ from the regular chain rule?

The vector chain rule is an extension of the regular chain rule, which only applies to functions of one variable. In the vector chain rule, we are dealing with functions of multiple variables, so the differentiation process becomes more complex and involves vectors and matrices.

Can you provide an example of how the vector chain rule is used in real-world applications?

One example of the vector chain rule in action is in the field of robotics. In order to control the motion of a robotic arm, we need to calculate the velocity and acceleration of each joint. This involves using the vector chain rule to find the derivative of the position, velocity, and acceleration vectors with respect to time.

Why might a proof for the vector chain rule seem confusing or nonsensical?

The vector chain rule can be difficult to understand at first because it involves multiple variables and vector operations. It also requires a strong understanding of calculus and linear algebra. If the proof for the vector chain rule makes no sense, it may be because the person does not have the necessary background knowledge.

What resources or methods can help in understanding and applying the vector chain rule?

One helpful resource for understanding the vector chain rule is to review the basic principles of calculus and linear algebra. There are also many online tutorials and videos that explain the concept in simpler terms. Practice problems and examples can also aid in comprehension and application of the vector chain rule.

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