Math Problem Statement

Consider the function y = 2 / ln((e^cos(x)) + 5). Find functions f, g, h, m and t such that y = f ◦ g ◦ h ◦ m ◦ t = f(g(h(m(t(x))))). Determine the domain of the overall function and state your answer in interval notation

Solution

To express y=2/ln(ecos(x)+5)y = 2 / \ln(e^{\cos(x)} + 5) as y=f(g(h(m(t(x)))))y = f(g(h(m(t(x))))), we need to break down the function into a composition of simpler functions. Here's how we can do this:

  1. Innermost function t(x)t(x): Start with t(x)=cos(x)t(x) = \cos(x).

  2. Next function m(t)m(t): Apply the exponential function to the result of t(x)t(x): m(t)=etm(t) = e^t Therefore, m(t(x))=ecos(x)m(t(x)) = e^{\cos(x)}.

  3. Next function h(m)h(m): Add 5 to the result of m(t)m(t): h(m)=m+5h(m) = m + 5 So, h(m(t(x)))=ecos(x)+5h(m(t(x))) = e^{\cos(x)} + 5.

  4. Next function g(h)g(h): Apply the natural logarithm to the result of h(m)h(m): g(h)=ln(h)g(h) = \ln(h) Hence, g(h(m(t(x))))=ln(ecos(x)+5)g(h(m(t(x)))) = \ln(e^{\cos(x)} + 5).

  5. Outermost function f(g)f(g): Take the reciprocal of g(h)g(h) and multiply by 2: f(g)=2gf(g) = \frac{2}{g} Therefore, f(g(h(m(t(x)))))=2ln(ecos(x)+5)f(g(h(m(t(x))))) = \frac{2}{\ln(e^{\cos(x)} + 5)}.

So the functions are:

t(x) &= \cos(x), \\ m(t) &= e^t, \\ h(m) &= m + 5, \\ g(h) &= \ln(h), \\ f(g) &= \frac{2}{g}. \end{aligned}$$ Now, the overall function $$y$$ can be expressed as: $$y = f(g(h(m(t(x))))) = \frac{2}{\ln(e^{\cos(x)} + 5)}.$$ ### Determining the Domain To find the domain, consider where each function in the composition is defined: 1. **$$t(x) = \cos(x)$$:** Defined for all $$x \in \mathbb{R}$$. 2. **$$m(t) = e^t$$:** Exponential functions are defined for all real numbers, so $$e^{\cos(x)}$$ is also defined for all $$x \in \mathbb{R}$$. 3. **$$h(m) = m + 5 = e^{\cos(x)} + 5$$:** Addition of 5 to $$e^{\cos(x)}$$ is defined for all $$x \in \mathbb{R}$$. 4. **$$g(h) = \ln(h)$$:** The natural logarithm function is defined for positive values. Therefore, $$e^{\cos(x)} + 5$$ must be greater than 0. Since $$e^{\cos(x)}$$ is always positive (it ranges from $$e^{-1}$$ to $$e^1$$), $$e^{\cos(x)} + 5$$ is always positive. Hence, $$\ln(e^{\cos(x)} + 5)$$ is defined for all $$x \in \mathbb{R}$$. 5. **$$f(g) = \frac{2}{g}$$:** We need to ensure that $$g \neq 0$$. Therefore, $$\ln(e^{\cos(x)} + 5)$$ must not be zero. $$\ln(e^{\cos(x)} + 5) = 0$$ implies $$e^{\cos(x)} + 5 = 1.$$ Since $$e^{\cos(x)} \geq e^{-1} \approx 0.3679$$ and $$e^{\cos(x)} + 5 \geq 5.3679$$, the expression $$e^{\cos(x)} + 5$$ can never be equal to 1. Thus, $$\ln(e^{\cos(x)} + 5)$$ is never zero. Since there are no restrictions making the function undefined, the domain of the overall function is all real numbers: $$\text{Domain} = (-\infty, \infty).$$ Would you like further details or have any questions about this process? ### Related Questions 1. How would the function change if the base of the logarithm were different? 2. What would the derivative of $$y = 2 / \ln(e^{\cos(x)} + 5)$$ be? 3. What is the range of the function $$y = 2 / \ln(e^{\cos(x)} + 5)$$? 4. How would the composition change if an additional transformation were applied to $$\cos(x)$$? 5. Can this composition be used to simplify integrals involving this function? ### Tip When determining the domain of a function, always look for operations that impose restrictions, such as square roots (must be non-negative inside), logarithms (must be positive inside), and denominators (must not be zero).

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Math Problem Analysis

Mathematical Concepts

Function Composition
Logarithmic Functions
Exponential Functions
Trigonometric Functions

Formulas

t(x) = cos(x)
m(t) = e^t
h(m) = m + 5
g(h) = ln(h)
f(g) = 2 / g

Theorems

Domain of logarithmic functions: ln(x) is defined when x > 0
Exponential functions: e^x is defined for all x ∈ ℝ
Cosine function is defined for all real numbers

Suitable Grade Level

Undergraduate - Calculus I/II