The diagram below shows the graphs of $g(x) = \frac{2}{x + p} + q$ and $f(x) = \log_{a} x$ - NSC Mathematics - Question 5 - 2017 - Paper 1
Question 5
The diagram below shows the graphs of $g(x) = \frac{2}{x + p} + q$ and $f(x) = \log_{a} x$.
- $y = -1$ is the horizontal asymptote of $g$.
- $B(1; 0)$ is the $x$... show full transcript
Worked Solution & Example Answer:The diagram below shows the graphs of $g(x) = \frac{2}{x + p} + q$ and $f(x) = \log_{a} x$ - NSC Mathematics - Question 5 - 2017 - Paper 1
Step 1
5.1 Write down the range of $g$.
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Answer
The range of the function g(x) is y∈(−∞,−1), as the horizontal asymptote is y=−1. Thus, the output values of g will always be less than -1.
Step 2
5.2 Determine the equation of $g$.
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Answer
To determine the equation of g, we need to analyze the components provided:
Given the vertical asymptote intersects the x-axis at E, we can express the equation of g as:
g(x)=x−22−1
This is obtained by considering the transformations reflected in the given diagram.
Step 3
5.3 Calculate the value of $t$.
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Answer
To find the value of t, we know A(t;1) is a point of intersection between f and g. Substituting 1 into the equation of f(x) gives:
f(t)=logat=1
This implies:
t=a1=a
We also know from the equation of g:
g(t)=t−22−1
Setting g(t) equal to 1 allows us to solve for t:
5.4 Write down the equation of $f^{-1}$, the inverse of $f$, in the form $y = ...$
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Answer
To find the inverse of f(x)=logax, we interchange x and y:
x=logay
Exponentiating both sides yields:
y=ax
Thus, the equation of f−1 is:
y=ax
Step 5
5.5 For which values of $x$ will $f^{-1}(g) < 3$?
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Answer
We need to solve:
f−1(g)<3⇒g<a3
Using the determined equation of g:
x−22−1<a3
Rearranging gives:
⇒x−22<a3+1
Thus, the inequality must be solved for x:
x<(a3+1)2+2
Step 6
5.6 Determine the point of intersection of the graphs of $f$ and the axis of symmetry of $g$ that has a negative gradient.
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Answer
The axis of symmetry is given by the equation:
y=−x+1
To find the intersection with f(x):
logax=−x+1
We calculate the point of intersection:
Solving this equation will provide the coordinates of the intersection that has a negative gradient.