Finding dy/dt using the chain rule and a given equation

In summary, to find dy/dt, differentiate the equation 4x^3-6xy^2+3y^2=228 with respect to t and substitute the given values for x, y, and dx/dt. Then, use the chain rule to find dy/dx and convert it to dy/dt.
  • #1
kweig
4
0

Homework Statement



So I'm trying to find dy/dt. I used the chain rule to find dx/dt. I just don't understand how to put that answer back into an equation to find dy/dt

Homework Equations



4x^3-6xy^2+3y^2=228

The Attempt at a Solution


I found dx/dt=3 x=-3 and y=4
So how/what equation do I use to find dy/dt
 
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  • #2
kweig said:

Homework Statement



So I'm trying to find dy/dt. I used the chain rule to find dx/dt. I just don't understand how to put that answer back into an equation to find dy/dt

Homework Equations



4x^3-6xy^2+3y^2=228

The Attempt at a Solution


I found dx/dt=3 x=-3 and y=4
So how/what equation do I use to find dy/dt

Differentiate 4x^3-6xy^2+3y^2=228 with respect to t, put your values for x, y and dx/dt into that and solve for dy/dt.
 
  • #3
The implicit differentiation?
 
  • #4
kweig said:
The implicit differentiation?

Of course.
 
  • #5
I got dy/dt=(2x^2-y^2)/(y(2x-1))
 
  • #6
kweig said:
I got dy/dt=(2x^2-y^2)/(y(2x-1))

An expression for dy/dt ought to have some dx/dt's in it. I think what you've got there is dy/dx. Can you think how to use that to get dy/dt?
 
  • #7
Yep! I figured it out. Thank you!
 

FAQ: Finding dy/dt using the chain rule and a given equation

What is the purpose of evaluating derivatives?

The purpose of evaluating derivatives is to find the rate of change of a function at a specific point. It allows us to understand how the function is changing and can be used to predict future values of the function.

How do you evaluate a derivative?

To evaluate a derivative, you need to use the derivative rule or formula for the specific type of function. This may involve taking the limit, finding the derivative of each term, or using the chain rule. Once you have applied the appropriate rule, you can plug in the given value to find the derivative at that point.

What is the difference between a derivative and a derivative function?

A derivative is the instantaneous rate of change of a function at a specific point. It is a single value. A derivative function, on the other hand, is a function that represents the derivative at each point of the original function. In other words, it is a function that gives the slope of the original function at any given point.

Why is it important to understand derivatives?

Understanding derivatives is important for various reasons. It is a fundamental concept in calculus and is used in many applications such as physics, engineering, economics, and statistics. It allows us to analyze the behavior of functions and make predictions. Additionally, derivatives are crucial in optimization problems, which are commonly encountered in many fields.

What are some common applications of derivatives?

Some common applications of derivatives include finding maximum and minimum values of a function, calculating velocity and acceleration in physics, determining marginal cost and revenue in economics, and analyzing the growth of populations in biology. Derivatives are also used in optimization problems, curve sketching, and in many other areas of mathematics and science.

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