Given the function $p(x) = \left( \frac{1}{3} \right)^x$:
4.1.1 Is $p$ an increasing or decreasing function?
4.1.2 Determine $p^{-1}$, the inverse of $p$, in the form $y = ...$
4.1.3 Write down the domain of $p^{-1}$ - NSC Mathematics - Question 4 - 2023 - Paper 1
Question 4
Given the function $p(x) = \left( \frac{1}{3} \right)^x$:
4.1.1 Is $p$ an increasing or decreasing function?
4.1.2 Determine $p^{-1}$, the inverse of $p$, in the f... show full transcript
Worked Solution & Example Answer:Given the function $p(x) = \left( \frac{1}{3} \right)^x$:
4.1.1 Is $p$ an increasing or decreasing function?
4.1.2 Determine $p^{-1}$, the inverse of $p$, in the form $y = ...$
4.1.3 Write down the domain of $p^{-1}$ - NSC Mathematics - Question 4 - 2023 - Paper 1
Step 1
Is $p$ an increasing or decreasing function?
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Answer
To determine if p(x) is an increasing or decreasing function, we analyze the base of the function, which is rac{1}{3}. Since rac{1}{3} < 1, the function p(x) is a decreasing function.
Step 2
Determine $p^{-1}$, the inverse of $p$, in the form $y = ...$
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Answer
To find the inverse of p(x):
Start with y=(31)x.
Swap x and y: x=(31)y.
Take the logarithm of both sides: log31(x)=y.
Thus, the inverse is p−1(x)=log31(x).
Step 3
Write down the domain of $p^{-1}$.
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Answer
The domain of the inverse function p−1(x)=log31(x) is x>0, since logarithms are defined only for positive numbers.
Step 4
Write down the equation of the asymptote of $p(x) - 5$.
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Answer
The asymptote of the function p(x) occurs where p(x) approaches a constant as x approaches infinity. Thus, for p(x)−5, the equation of the asymptote is y=−5.
Step 5
Write down the equations of the asymptotes of $f$.
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Answer
The function f(x)=x−14+2 has:
A vertical asymptote at x=1 (where the denominator is zero).
A horizontal asymptote at y=2 (as x→∞).
Step 6
Calculate the x-intercept of $f$.
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Answer
To find the x-intercept, set f(x)=0:
0=x−14+2
Rearranging gives:
x−14=−24=−2(x−1)4=−2x+22=−2xx=−1
Thus, the x-intercept is x=−1.
Step 7
Sketch the graph of $f$, label all asymptotes and indicate the intercepts with the axes.
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Answer
To sketch the graph of f(x):
Mark the vertical asymptote at x=1 and the horizontal asymptote at y=2.
Plot the x-intercept at (−1,0).
The graph approaches the horizontal asymptote as x approaches infinity and diverges as it approaches the vertical asymptote.
Step 8
Use your graph to determine the values of $x$ for which $\frac{4}{x - 1} = -2$.
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Answer
To find the values of x for which x−14=−2, we solve:
From our previous calculation: x=2
Thus, x=2 is the value satisfying the equation.
Step 9
Determine the equation of the axis of symmetry of $f(x - 2)$, that has a negative gradient.
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Answer
The axis of symmetry for the function f(x−2)=(x−2)−14+2 is determined by finding the x-coordinate of the vertex. The transformation f(x−2) shifts the function two units to the right. The symmetry line would be at x=2, with a negative gradient of the original function.