Skip to main content
Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 7, Problem 7.PE.79

In Exercises 79–84, solve for y.
79. 3^y = 2^(y+1)

Verified step by step guidance
1
Start with the given equation: \(3^{y} = 2^{y+1}\).
Rewrite the right side using exponent rules: \(2^{y+1} = 2^{y} \cdot 2^{1} = 2^{y} \cdot 2\).
Express the equation as \(3^{y} = 2 \cdot 2^{y}\).
Divide both sides by \$2^{y}\( to isolate terms involving \)y$: \(\frac{3^{y}}{2^{y}} = 2\).
Rewrite the left side as a single exponential: \(\left(\frac{3}{2}\right)^{y} = 2\). Then, take the natural logarithm of both sides to solve for \(y\): \(y \cdot \ln\left(\frac{3}{2}\right) = \ln(2)\).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Exponential Equations

Exponential equations involve variables in the exponent position, such as 3^y or 2^(y+1). Solving these requires techniques to isolate the variable, often by rewriting the equation or applying logarithms.
Recommended video:
5:47
Solving Exponential Equations Using Logs

Properties of Logarithms

Logarithms are the inverse operations of exponentials and help solve equations where the variable is an exponent. Key properties include log(a^b) = b log(a), which allows bringing down exponents to solve for the variable.
Recommended video:
05:36
Change of Base Property

Equating and Simplifying Exponents

When bases differ and cannot be rewritten to a common base, taking logarithms on both sides allows comparison of exponents. Simplifying the resulting equation leads to isolating the variable and finding its value.
Recommended video:
Guided course
6:39
Simplifying Exponential Expressions