Math Problem Statement

Find the x- and y-intercepts of the given

f(x)=3^(x+1)−4

Solution

To find the x- and y-intercepts of the function f(x)=3x+14f(x) = 3^{x+1} - 4, follow these steps:

1. Finding the y-intercept:

The y-intercept occurs where x=0x = 0.

f(0)=30+14=314=34=1f(0) = 3^{0+1} - 4 = 3^1 - 4 = 3 - 4 = -1

Thus, the y-intercept is at (0,1)(0, -1).

2. Finding the x-intercept:

The x-intercept occurs where f(x)=0f(x) = 0. Set the function equal to 0 and solve for xx:

0=3x+140 = 3^{x+1} - 4 3x+1=43^{x+1} = 4 Now, take the natural logarithm (or logarithm base 3) of both sides:

x+1=log3(4)x + 1 = \log_3(4) Convert this to a natural log if needed:

x+1=ln(4)ln(3)x + 1 = \frac{\ln(4)}{\ln(3)} x=ln(4)ln(3)1x = \frac{\ln(4)}{\ln(3)} - 1

Calculating the values:

x1.3861.09911.26110.261x \approx \frac{1.386}{1.099} - 1 \approx 1.261 - 1 \approx 0.261

Thus, the x-intercept is approximately (0.261,0)(0.261, 0).

Summary:

  • The y-intercept is at (0,1)(0, -1).
  • The x-intercept is approximately at (0.261,0)(0.261, 0).

Would you like further explanation or clarification on any of the steps?


Here are 5 related questions to explore further:

  1. How do you graph exponential functions like f(x)=3x+14f(x) = 3^{x+1} - 4?
  2. What is the general form of an exponential function?
  3. How do logarithmic properties help in solving equations like 3x+1=43^{x+1} = 4?
  4. How do transformations affect the intercepts of exponential functions?
  5. What is the domain and range of f(x)=3x+14f(x) = 3^{x+1} - 4?

Tip: When solving for x-intercepts in exponential equations, logarithms are often the best tool to simplify the expression.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Logarithms
Intercepts

Formulas

y-intercept: f(0) = 3^(0+1) - 4
x-intercept: 0 = 3^(x+1) - 4
logarithmic conversion: x + 1 = log_3(4)

Theorems

Properties of Exponential Functions
Logarithmic Conversion Theorem

Suitable Grade Level

Grades 10-12