If $f(x) = \frac{3x + 3}{5x + 6}$, Find:1. $f^{\prime}(x) =$2. $f^{\prime}(4) =$

by ADMIN 81 views

If f(x)=3x+35x+6f(x) = \frac{3x + 3}{5x + 6}, find: 1. $f^{\prime}(x) =$2. fβ€²(4)=f^{\prime}(4) =

In this article, we will explore the concept of finding the derivative of a given function and then evaluating it at a specific point. The function in question is f(x)=3x+35x+6f(x) = \frac{3x + 3}{5x + 6}. We will first find the derivative of this function, denoted as fβ€²(x)f^{\prime}(x), and then evaluate it at x=4x = 4.

To find the derivative of a function, we can use the quotient rule, which states that if we have a function of the form f(x)=g(x)h(x)f(x) = \frac{g(x)}{h(x)}, then the derivative of this function is given by:

fβ€²(x)=h(x)gβ€²(x)βˆ’g(x)hβ€²(x)(h(x))2f^{\prime}(x) = \frac{h(x)g^{\prime}(x) - g(x)h^{\prime}(x)}{(h(x))^2}

In our case, we have g(x)=3x+3g(x) = 3x + 3 and h(x)=5x+6h(x) = 5x + 6. We can find the derivatives of these functions as follows:

gβ€²(x)=3g^{\prime}(x) = 3

hβ€²(x)=5h^{\prime}(x) = 5

Now, we can plug these values into the quotient rule formula:

fβ€²(x)=(5x+6)(3)βˆ’(3x+3)(5)(5x+6)2f^{\prime}(x) = \frac{(5x + 6)(3) - (3x + 3)(5)}{(5x + 6)^2}

Simplifying this expression, we get:

fβ€²(x)=15x+18βˆ’15xβˆ’15(5x+6)2f^{\prime}(x) = \frac{15x + 18 - 15x - 15}{(5x + 6)^2}

fβ€²(x)=3(5x+6)2f^{\prime}(x) = \frac{3}{(5x + 6)^2}

Now that we have found the derivative of the function, we can evaluate it at x=4x = 4. Plugging x=4x = 4 into the derivative, we get:

fβ€²(4)=3(5(4)+6)2f^{\prime}(4) = \frac{3}{(5(4) + 6)^2}

fβ€²(4)=3(26)2f^{\prime}(4) = \frac{3}{(26)^2}

fβ€²(4)=3676f^{\prime}(4) = \frac{3}{676}

In this article, we found the derivative of the function f(x)=3x+35x+6f(x) = \frac{3x + 3}{5x + 6} and then evaluated it at x=4x = 4. We used the quotient rule to find the derivative and then simplified the expression to get the final answer. The derivative of the function is fβ€²(x)=3(5x+6)2f^{\prime}(x) = \frac{3}{(5x + 6)^2}, and the value of the derivative at x=4x = 4 is fβ€²(4)=3676f^{\prime}(4) = \frac{3}{676}.

Here is a step-by-step solution to the problem:

  1. Find the derivatives of g(x)=3x+3g(x) = 3x + 3 and h(x)=5x+6h(x) = 5x + 6.
  2. Plug these values into the quotient rule formula.
  3. Simplify the expression to get the final answer.
  4. Evaluate the derivative at x=4x = 4.

Here are some common mistakes to avoid when finding the derivative of a function:

  • Not using the quotient rule when the function is in the form f(x)=g(x)h(x)f(x) = \frac{g(x)}{h(x)}.
  • Not simplifying the expression after finding the derivative.
  • Not evaluating the derivative at the correct point.

The concept of finding the derivative of a function has many real-world applications. For example:

  • In physics, the derivative of a function can be used to find the velocity and acceleration of an object.
  • In economics, the derivative of a function can be used to find the marginal cost and marginal revenue of a product.
  • In engineering, the derivative of a function can be used to find the slope of a curve and the rate of change of a quantity.

In our previous article, we explored the concept of finding the derivative of a function and evaluating it at a specific point. We used the quotient rule to find the derivative of the function f(x)=3x+35x+6f(x) = \frac{3x + 3}{5x + 6} and then evaluated it at x=4x = 4. In this article, we will answer some common questions related to finding the derivative of a function.

Q: What is the quotient rule?

A: The quotient rule is a formula for finding the derivative of a function that is in the form f(x)=g(x)h(x)f(x) = \frac{g(x)}{h(x)}. The quotient rule states that the derivative of this function is given by:

fβ€²(x)=h(x)gβ€²(x)βˆ’g(x)hβ€²(x)(h(x))2f^{\prime}(x) = \frac{h(x)g^{\prime}(x) - g(x)h^{\prime}(x)}{(h(x))^2}

Q: How do I find the derivative of a function using the quotient rule?

A: To find the derivative of a function using the quotient rule, you need to follow these steps:

  1. Identify the functions g(x)g(x) and h(x)h(x).
  2. Find the derivatives of g(x)g(x) and h(x)h(x).
  3. Plug these values into the quotient rule formula.
  4. Simplify the expression to get the final answer.

Q: What is the difference between the quotient rule and the product rule?

A: The quotient rule and the product rule are two different formulas for finding the derivative of a function. The quotient rule is used when the function is in the form f(x)=g(x)h(x)f(x) = \frac{g(x)}{h(x)}, while the product rule is used when the function is in the form f(x)=g(x)h(x)f(x) = g(x)h(x). The product rule states that the derivative of this function is given by:

fβ€²(x)=gβ€²(x)h(x)+g(x)hβ€²(x)f^{\prime}(x) = g^{\prime}(x)h(x) + g(x)h^{\prime}(x)

Q: How do I evaluate the derivative of a function at a specific point?

A: To evaluate the derivative of a function at a specific point, you need to plug the value of the point into the derivative. For example, if we want to evaluate the derivative of the function f(x)=3x+35x+6f(x) = \frac{3x + 3}{5x + 6} at x=4x = 4, we would plug x=4x = 4 into the derivative:

fβ€²(4)=3(5(4)+6)2f^{\prime}(4) = \frac{3}{(5(4) + 6)^2}

Q: What are some common mistakes to avoid when finding the derivative of a function?

A: Some common mistakes to avoid when finding the derivative of a function include:

  • Not using the correct formula for the derivative.
  • Not simplifying the expression after finding the derivative.
  • Not evaluating the derivative at the correct point.

Q: What are some real-world applications of finding the derivative of a function?

A: The concept of finding the derivative of a function has many real-world applications, including:

  • In physics, the derivative of a function can be used to find the velocity and acceleration of an object.
  • In economics, the derivative of a function can be used to find the marginal cost and marginal revenue of a product.
  • In engineering, the derivative of a function can be used to find the slope of a curve and the rate of change of a quantity.

In conclusion, finding the derivative of a function and evaluating it at a specific point is an important concept in mathematics. The quotient rule is a useful tool for finding the derivative of a function, and the concept of finding the derivative has many real-world applications. By following the steps outlined in this article, you can find the derivative of a function and evaluate it at a specific point.

For more information on finding the derivative of a function, you can consult the following resources:

  • Calculus textbooks
  • Online tutorials and videos
  • Math websites and forums

Here are some practice problems to help you practice finding the derivative of a function:

  1. Find the derivative of the function f(x)=2x+13xβˆ’2f(x) = \frac{2x + 1}{3x - 2}.
  2. Evaluate the derivative of the function f(x)=3x+24xβˆ’1f(x) = \frac{3x + 2}{4x - 1} at x=3x = 3.
  3. Find the derivative of the function f(x)=(2x+1)(3xβˆ’2)f(x) = (2x + 1)(3x - 2).

Here are the answers to the practice problems:

  1. fβ€²(x)=3(3xβˆ’2)βˆ’(2x+1)(3)(3xβˆ’2)2f^{\prime}(x) = \frac{3(3x - 2) - (2x + 1)(3)}{(3x - 2)^2}
  2. fβ€²(3)=3(4)βˆ’(5)(3)(4)2=12βˆ’1516=βˆ’316f^{\prime}(3) = \frac{3(4) - (5)(3)}{(4)^2} = \frac{12 - 15}{16} = -\frac{3}{16}
  3. fβ€²(x)=6xβˆ’6f^{\prime}(x) = 6x - 6