Write An Exponential Function In The Form Y = A B X Y = Ab^x Y = A B X That Goes Through The Points ( 0 , 9 (0, 9 ( 0 , 9 ] And ( 5 , 2187 (5, 2187 ( 5 , 2187 ].

by ADMIN 162 views

Introduction

Exponential functions are a fundamental concept in mathematics, used to model real-world phenomena that exhibit rapid growth or decay. In this article, we will explore how to write an exponential function in the form y=abxy = ab^x that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187).

What are Exponential Functions?

Exponential functions are a type of mathematical function that can be written in the form y=abxy = ab^x, where aa and bb are constants, and xx is the variable. The base bb is a positive real number, and the exponent xx is a real number. Exponential functions are used to model situations where a quantity grows or decays at a constant rate.

The General Form of an Exponential Function

The general form of an exponential function is y=abxy = ab^x, where aa and bb are constants, and xx is the variable. The base bb is a positive real number, and the exponent xx is a real number. The value of aa determines the initial value of the function, while the value of bb determines the rate of growth or decay.

Finding the Exponential Function that Passes Through the Given Points

To find the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187), we need to use the given points to set up a system of equations. We can start by substituting the values of xx and yy from the given points into the general form of the exponential function.

Step 1: Substitute the Values of xx and yy from the Given Points

Let's substitute the values of xx and yy from the given points into the general form of the exponential function.

  • For the point (0,9)(0, 9), we have y=9y = 9 and x=0x = 0. Substituting these values into the general form of the exponential function, we get: 9=ab09 = ab^0
  • For the point (5,2187)(5, 2187), we have y=2187y = 2187 and x=5x = 5. Substituting these values into the general form of the exponential function, we get: 2187=ab52187 = ab^5

Step 2: Simplify the Equations

Now that we have substituted the values of xx and yy from the given points into the general form of the exponential function, we can simplify the equations.

  • For the point (0,9)(0, 9), we have 9=ab09 = ab^0. Since b0=1b^0 = 1, we can simplify this equation to: 9=a9 = a
  • For the point (5,2187)(5, 2187), we have 2187=ab52187 = ab^5. We can substitute the value of aa from the previous equation into this equation to get: 2187=9b52187 = 9b^5

Step 3: Solve for bb

Now that we have simplified the equations, we can solve for bb.

  • From the equation 2187=9b52187 = 9b^5, we can divide both sides by 9 to get: 243=b5243 = b^5
  • Taking the fifth root of both sides, we get: b=3b = 3

Step 4: Write the Exponential Function

Now that we have found the value of bb, we can write the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187).

  • Since a=9a = 9 and b=3b = 3, we can substitute these values into the general form of the exponential function to get: y=9(3x)y = 9(3^x)

Conclusion

In this article, we have shown how to write an exponential function in the form y=abxy = ab^x that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187). We have used the given points to set up a system of equations, simplified the equations, and solved for bb. Finally, we have written the exponential function that passes through the given points.

Exponential Functions in Real-World Applications

Exponential functions have many real-world applications, including:

  • Population growth: Exponential functions can be used to model population growth, where the population grows at a constant rate.
  • Compound interest: Exponential functions can be used to model compound interest, where the interest rate is applied to the principal amount at regular intervals.
  • Radioactive decay: Exponential functions can be used to model radioactive decay, where the amount of radioactive material decreases at a constant rate.

Common Mistakes to Avoid

When working with exponential functions, there are several common mistakes to avoid:

  • Incorrectly substituting values: Make sure to substitute the correct values of xx and yy from the given points into the general form of the exponential function.
  • Simplifying equations incorrectly: Make sure to simplify the equations correctly, and avoid making mistakes when solving for bb.
  • Writing the exponential function incorrectly: Make sure to write the exponential function correctly, using the correct values of aa and bb.

Final Thoughts

Q&A: Exponential Functions

Q: What is an exponential function?

A: An exponential function is a type of mathematical function that can be written in the form y=abxy = ab^x, where aa and bb are constants, and xx is the variable. The base bb is a positive real number, and the exponent xx is a real number.

Q: What is the general form of an exponential function?

A: The general form of an exponential function is y=abxy = ab^x, where aa and bb are constants, and xx is the variable. The base bb is a positive real number, and the exponent xx is a real number.

Q: How do I find the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187)?

A: To find the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187), you need to use the given points to set up a system of equations. You can start by substituting the values of xx and yy from the given points into the general form of the exponential function.

Q: What are the steps to find the exponential function that passes through the given points?

A: The steps to find the exponential function that passes through the given points are:

  1. Substitute the values of xx and yy from the given points into the general form of the exponential function.
  2. Simplify the equations.
  3. Solve for bb.
  4. Write the exponential function.

Q: What is the value of bb in the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187)?

A: The value of bb in the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187) is 33.

Q: What is the exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187)?

A: The exponential function that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187) is y=9(3x)y = 9(3^x).

Q: What are some real-world applications of exponential functions?

A: Exponential functions have many real-world applications, including:

  • Population growth
  • Compound interest
  • Radioactive decay

Q: What are some common mistakes to avoid when working with exponential functions?

A: Some common mistakes to avoid when working with exponential functions include:

  • Incorrectly substituting values
  • Simplifying equations incorrectly
  • Writing the exponential function incorrectly

Q: How can I use exponential functions to model real-world phenomena?

A: You can use exponential functions to model real-world phenomena by:

  • Using the general form of the exponential function to model the phenomenon
  • Substituting the values of xx and yy from the given data into the general form of the exponential function
  • Simplifying the equations
  • Solving for bb
  • Writing the exponential function

Q: What are some tips for working with exponential functions?

A: Some tips for working with exponential functions include:

  • Make sure to substitute the correct values of xx and yy from the given points into the general form of the exponential function.
  • Simplify the equations correctly, and avoid making mistakes when solving for bb.
  • Write the exponential function correctly, using the correct values of aa and bb.

Conclusion

Exponential functions are a powerful tool for modeling real-world phenomena that exhibit rapid growth or decay. By following the steps outlined in this article, you can write an exponential function in the form y=abxy = ab^x that passes through the points (0,9)(0, 9) and (5,2187)(5, 2187). Remember to avoid common mistakes, and to use exponential functions to model real-world applications.