Chapter 8: Problem 23
Check that the functions are inverses. $$ f(x)=32 x^{5}-2 \text { and } g(t)=\frac{(t+2)^{1 / 5}}{2} $$
Short Answer
Expert verified
Answer: Yes, the functions are inverses of each other since $$f(g(t)) = t$$ and $$g(f(x)) = x$$.
Step by step solution
01
Find the composition f(g(t))
To find f(g(t)), substitute g(t) into f(x):
$$
f(g(t)) = 32\left(\frac{(t+2)^{1/5}}{2}\right)^5 - 2
$$
02
Simplify f(g(t))
Let's simplify the equation by applying the power to the g(t) function:
$$
f(g(t)) = 32\left(\frac{(t+2)^{1}}{32}\right) - 2
$$
Cancel out the 32 with the denominator,
$$
f(g(t)) = t + 2 - 2
$$
Simplify further,
$$
f(g(t)) = t
$$
03
Find the composition g(f(x))
To find g(f(x)), substitute f(x) into g(t):
$$
g(f(x)) = \frac{(32 x^5 - 2 + 2)^{1/5}}{2}
$$
04
Simplify g(f(x))
Let's simplify the equation by removing the constants from the parenthesis:
$$
g(f(x)) = \frac{(32 x^5)^{1/5}}{2}
$$
Use the property of exponentiation to simplify this further,
$$
g(f(x)) = \frac{2x}{2}
$$
The denominator cancels with the numerator,
$$
g(f(x)) = x
$$
Since f(g(t)) = t and g(f(x)) = x, we have proven that f(x) and g(t) are inverse functions.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Function Composition
Function composition is like building a machine inside another. To check if two functions are inverses, we often perform function composition. This means you plug the output of one function into another function. In math, this is represented as \( f(g(t)) \) and \( g(f(x)) \). If after plugging one function into the other, you end up back where you started, then the functions are inverses.
For instance, to determine if \( f(x) = 32x^5 - 2 \) and \( g(t) = \frac{(t+2)^{1/5}}{2} \) are inverses, you compute \( f(g(t)) \) and \( g(f(x)) \).
For instance, to determine if \( f(x) = 32x^5 - 2 \) and \( g(t) = \frac{(t+2)^{1/5}}{2} \) are inverses, you compute \( f(g(t)) \) and \( g(f(x)) \).
- In \( f(g(t)) \), substitute \( g(t) \) where \( x \) appears in \( f(x) \).
- In \( g(f(x)) \), substitute \( f(x) \) where \( t \) appears in \( g(t) \).
Exponents
Exponents can often seem tricky, but they simplify many mathematical expressions. In this situation, we deal with exponents of 5 and \( \frac{1}{5} \). These represent raising a number to the fifth power and finding the fifth root.Opposite operations like these cancel each other out, another reason they show two functions are inverses.
In our problem, observe:
In our problem, observe:
- \( 32x^5 \) indicates \( x \) multiplied by itself five times, then scaled up by 32.
- \( (t+2)^{1/5} \) calculates the fifth root. When these operations occur together, as in our function pair, they counterbalance, simplifying to return the original number.
Simplification
Simplification means breaking down complicated expressions into simpler forms. This involves arithmetic operations - adding, subtracting, multiplying, dividing - and other actions, like canceling out terms. In mathematics, simpler expressions often reveal underlying truths more clearly.
Through simplification:
Through simplification:
- In \( f(g(t)) = 32\left(\frac{(t+2)^{1/5}}{2}\right)^5 - 2 \), operations cancel each other, leaving \( t \), so \( f(g(t)) = t \).
- Similarly, \( g(f(x)) = \frac{(32x^5 - 2 + 2)^{1/5}}{2} \) simplifies to \( x \).
Algebraic Functions
Algebraic functions encompass a wide range of mathematical expressions including polynomials, roots, and rational expressions. The main goal is evaluating how these expressions behave with manipulations such as addition or composition.
Take the algebraic functions we’re dealing with: v
Take the algebraic functions we’re dealing with: v
- \( f(x) = 32x^5 - 2 \) is a polynomial function, where power and coefficients dictate its form.
- \( g(t) = \frac{(t+2)^{1/5}}{2} \) employs roots and division, showcasing a different algebraic structure.