뒤로Business Calculus: Exponential and Logarithmic Functions Review
스터디 가이드 - 스마트 노트
자료에 맞춘 맞춤형 노트, 핵심 정의, 예시, 맥락을 확장해 제공합니다.
Q1. Analyze the function :
Background
Topic: Exponential Functions and Transformations
This question tests your understanding of how to graph exponential functions, determine their domain and range, find the y-intercept, and identify the horizontal asymptote.
Key Terms and Formulas:
Exponential function: is the base function.
Transformation: Adding a constant outside the function, as in , shifts the graph vertically.
Domain: Set of all possible -values.
Range: Set of all possible -values.
y-intercept: The value of .
Horizontal asymptote: The line that the function approaches as .
Step-by-Step Guidance
Start by recalling the graph of . This function is always positive and increases rapidly as increases.
Recognize that adding 6 to shifts the entire graph up by 6 units. So, .
Determine the domain: Exponential functions are defined for all real numbers, so consider what this means for .
Determine the range: Since is always positive, will always be greater than 6. Think about how to express this in interval notation.
Find the y-intercept by evaluating . Substitute into the function and simplify.
Identify the horizontal asymptote by considering the behavior of as .
Try solving on your own before revealing the answer!
Final Answers:
Domain:
Range:
y-intercept:
Horizontal asymptote:
The function is defined for all real , always greater than 6, crosses the y-axis at 7, and approaches as .
Q2. Analyze the function :
Background
Topic: Exponential Functions and Transformations
This question is similar to the previous one but involves a reflection and a vertical shift. You are asked to determine the domain, range, y-intercept, and horizontal asymptote.
Key Terms and Formulas:
Reflection: reflects across the y-axis.
Vertical shift: Adding 3 shifts the graph up by 3 units.
Other terms as in Q1.
Step-by-Step Guidance
Recall the graph of , which decreases as increases.
Adding 3 shifts the graph up by 3 units, so .
Determine the domain: Exponential functions are defined for all real .
Determine the range: Since is always positive, will always be greater than 3.
Find the y-intercept by evaluating . Substitute into the function and simplify.
Identify the horizontal asymptote by considering the behavior as .
Try solving on your own before revealing the answer!
Final Answers:
Domain:
Range:
y-intercept:
Horizontal asymptote:
The function is defined for all real , always greater than 3, crosses the y-axis at 4, and approaches as .
Q3. Express as a difference of logarithms.
Background
Topic: Logarithmic Properties
This question tests your knowledge of the properties of logarithms, specifically how to rewrite the logarithm of a quotient as a difference.
Key Terms and Formulas:
Quotient Rule for Logarithms:
Step-by-Step Guidance
Identify the numerator and denominator inside the logarithm: and .
Recall the quotient rule for logarithms.
Apply the rule to rewrite as a difference of two logarithms.
Try solving on your own before revealing the answer!
Final Answer:
This uses the quotient rule for logarithms.
Q4. Rewrite as a sum or difference of multiples of logarithms.
Background
Topic: Logarithmic Expansion
This question tests your ability to expand logarithmic expressions using the product and power rules.
Key Terms and Formulas:
Product Rule:
Power Rule:
Step-by-Step Guidance
Identify the factors inside the logarithm: , , and .
Apply the product rule to separate the logarithm into a sum.
Apply the power rule to bring the exponents in front of the logarithms.
Try solving on your own before revealing the answer!
Final Answer:
Each exponent becomes a coefficient in front of the corresponding logarithm.
Q5. Solve for in .
Background
Topic: Solving Exponential Equations
This question tests your ability to solve for the exponent in an exponential equation using logarithms.
Key Terms and Formulas:
Exponential Equation:
Logarithmic Form:
Change of Base Formula:
Step-by-Step Guidance
Take the natural logarithm (or logarithm of any base) of both sides: .
Use the power rule to bring down: .
Solve for by dividing both sides by .
Set up the expression for but do not compute the final value yet.
Try solving on your own before revealing the answer!
Final Answer:
We used logarithms to isolate and then evaluated the expression to four decimal places.
Q6. Solve for in .
Background
Topic: Solving Exponential Equations with Base
This question tests your ability to solve for the exponent when the base is using natural logarithms.
Key Terms and Formulas:
Natural Logarithm: is the logarithm with base .
Inverse Property:
Step-by-Step Guidance
Take the natural logarithm of both sides: .
Use the property to simplify the left side.
Solve for by setting .
Set up the expression for but do not compute the final value yet.
Try solving on your own before revealing the answer!
Final Answer:
We used the natural logarithm to isolate and evaluated to four decimal places.
Q7. Write as a logarithmic equation.
Background
Topic: Exponential and Logarithmic Equations
This question tests your ability to convert between exponential and logarithmic forms.
Key Terms and Formulas:
Exponential Form:
Logarithmic Form:
Step-by-Step Guidance
Identify the base (), exponent (), and result ().
Recall the relationship: is equivalent to .
Write the logarithmic equation using these values.
Try solving on your own before revealing the answer!
Final Answer:
This is the equivalent logarithmic equation for the given exponential equation.
Q8. Write in equivalent exponential form.
Background
Topic: Exponential and Logarithmic Equations
This question tests your ability to convert a logarithmic equation to its equivalent exponential form.
Key Terms and Formulas:
Logarithmic Form:
Exponential Form:
Step-by-Step Guidance
Identify the base (), the argument (), and the result ().
Recall that is equivalent to .
Write the exponential equation using these values.
Try solving on your own before revealing the answer!
Final Answer:
This is the equivalent exponential form of the given logarithmic equation.
Q9. Determine the value of if .
Background
Topic: Solving Logarithmic Equations
This question tests your ability to solve for the argument of a logarithm given its value.
Key Terms and Formulas:
Logarithmic Form:
Exponential Form:
Step-by-Step Guidance
Rewrite the logarithmic equation in exponential form: .
Calculate to find the value of .
Try solving on your own before revealing the answer!
Final Answer:
We converted the logarithmic equation to exponential form and evaluated .
Q10. Determine the value of if .
Background
Topic: Solving Logarithmic Equations for the Base
This question tests your ability to solve for the base of a logarithm given the argument and the value.
Key Terms and Formulas:
Logarithmic Form:
Exponential Form:
Step-by-Step Guidance
Rewrite the logarithmic equation in exponential form: .
Recall that is the same as .
Set up the equation and solve for by squaring both sides.
Try solving on your own before revealing the answer!
Final Answer:
We squared both sides to solve for and found .