1. **Problem statement:**
We have two functions:
$$f(x) = \ln(x^2 + 3), \quad x \in \mathbb{R}$$
$$g(x) = \frac{3}{5} + \frac{2}{x + x}, \quad x \in \mathbb{R}, x > -2$$
We need to:
(a) State the range of $f$
(b) Find $g^{-1}$
(c) Find $f(g(0))$
(d) Find the exact value of $a$ for which $g(e^{f(e^2)}) = 4a + 3$
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2. **(a) Find the range of $f$:**
- The function is $f(x) = \ln(x^2 + 3)$.
- Since $x^2 \geq 0$ for all real $x$, the minimum value inside the logarithm is when $x=0$, giving $x^2 + 3 = 3$.
- The expression inside the logarithm, $x^2 + 3$, ranges from $3$ to $+\infty$.
- The natural logarithm function $\ln(y)$ is increasing for $y > 0$, so the minimum value of $f(x)$ is $\ln(3)$ and it increases without bound.
**Range of $f$ is:**
$$[\ln(3), +\infty)$$
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3. **(b) Find $g^{-1}$:**
- Given $g(x) = \frac{3}{5} + \frac{2}{x + x} = \frac{3}{5} + \frac{2}{2x} = \frac{3}{5} + \frac{1}{x}$ for $x > -2$.
- Let $y = g(x) = \frac{3}{5} + \frac{1}{x}$.
- Solve for $x$:
$$y - \frac{3}{5} = \frac{1}{x}$$
$$x = \frac{1}{y - \frac{3}{5}} = \frac{1}{y - 0.6}$$
**Therefore,**
$$g^{-1}(y) = \frac{1}{y - \frac{3}{5}}$$
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4. **(c) Find $f(g(0))$:**
- First find $g(0)$:
$$g(0) = \frac{3}{5} + \frac{1}{0}$$
- Division by zero is undefined, so $g(0)$ is undefined.
**Therefore, $f(g(0))$ is undefined.**
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5. **(d) Find exact value of $a$ such that $g(e^{f(e^2)}) = 4a + 3$:**
- Compute $f(e^2)$:
$$f(e^2) = \ln((e^2)^2 + 3) = \ln(e^{4} + 3)$$
- Then compute $e^{f(e^2)}$:
$$e^{f(e^2)} = e^{\ln(e^{4} + 3)} = e^{4} + 3$$
- Now compute $g(e^{f(e^2)}) = g(e^{4} + 3)$:
$$g(x) = \frac{3}{5} + \frac{1}{x}$$
$$g(e^{4} + 3) = \frac{3}{5} + \frac{1}{e^{4} + 3}$$
- Set equal to $4a + 3$:
$$\frac{3}{5} + \frac{1}{e^{4} + 3} = 4a + 3$$
- Solve for $a$:
$$4a = \frac{3}{5} + \frac{1}{e^{4} + 3} - 3$$
$$4a = \frac{3}{5} - 3 + \frac{1}{e^{4} + 3} = \frac{3}{5} - \frac{15}{5} + \frac{1}{e^{4} + 3} = -\frac{12}{5} + \frac{1}{e^{4} + 3}$$
$$a = \frac{1}{4} \left(-\frac{12}{5} + \frac{1}{e^{4} + 3}\right) = -\frac{3}{5} + \frac{1}{4(e^{4} + 3)}$$
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**Final answers:**
- (a) Range of $f$: $[\ln(3), +\infty)$
- (b) $g^{-1}(y) = \frac{1}{y - \frac{3}{5}}$
- (c) $f(g(0))$ is undefined
- (d) $a = -\frac{3}{5} + \frac{1}{4(e^{4} + 3)}$
Function Analysis 183Fc1
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