Uranium dating Uranium-238 (U-238) has a half-life of 4.5 billion years. Geologists find a rock containing a mixture of U-238 and lead, and they determine that 85% of the original U-238 remains; the other 15% has decayed into lead. How old is the rock?
Table of contents
- 0. Functions7h 54m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms36m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 3h 16m
- 11. Integrals of Inverse, Exponential, & Logarithmic Functions2h 34m
- 12. Techniques of Integration7h 41m
- 13. Intro to Differential Equations2h 55m
- 14. Sequences & Series5h 36m
- 15. Power Series2h 19m
- 16. Parametric Equations & Polar Coordinates7h 58m
0. Functions
Exponential Functions
Problem 7.3.43d
Textbook Question
Explain why or why not Determine whether the following statements are true and give an explanation or counterexample.
d. If the rate constant of an exponential growth function is increased, its doubling time is decreased.
Verified step by step guidance1
Recall the general form of an exponential growth function: \(N(t) = N_0 e^{kt}\), where \(k\) is the rate constant and \(k > 0\) for growth.
Understand that the doubling time \(T\) is the time it takes for the quantity to double, so \(N(T) = 2N_0\).
Set up the equation for doubling time: \$2N_0 = N_0 e^{kT}\(, which simplifies to \)2 = e^{kT}$.
Take the natural logarithm of both sides to solve for \(T\): \(\ln(2) = kT\), so \(T = \frac{\ln(2)}{k}\).
Analyze the relationship: since \(\ln(2)\) is constant, if the rate constant \(k\) increases, the denominator increases, making \(T\) smaller. Therefore, increasing the rate constant decreases the doubling time.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
2mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Exponential Growth Function
An exponential growth function models quantities that increase at a rate proportional to their current value, typically expressed as f(t) = f_0 * e^(kt), where k > 0 is the growth rate constant. This function describes processes like population growth or compound interest.
Recommended video:
Exponential Growth & Decay
Rate Constant and Its Effect
The rate constant k in an exponential growth function determines how quickly the quantity grows. A larger k means the function grows faster, causing the value to increase more rapidly over time compared to a smaller k.
Recommended video:
Intro To Related Rates
Doubling Time in Exponential Growth
Doubling time is the time required for an exponentially growing quantity to double in size. It is calculated as T = ln(2)/k, showing that as the rate constant k increases, the doubling time decreases, meaning the quantity doubles faster.
Recommended video:
Exponential Growth & Decay
Watch next
Master Exponential Functions with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice
Textbook Question
17
views
