In the diagram, the graphs of $f(x) = ext{log}_a x$ and $g$ are drawn - NSC Mathematics - Question 5 - 2024 - Paper 1
Question 5
In the diagram, the graphs of $f(x) = ext{log}_a x$ and $g$ are drawn. Graph $g$ is the reflection of $f$ in the line $y = x$. Graph $f$ passes through the point $P... show full transcript
Worked Solution & Example Answer:In the diagram, the graphs of $f(x) = ext{log}_a x$ and $g$ are drawn - NSC Mathematics - Question 5 - 2024 - Paper 1
Step 1
5.1 Write down the coordinates of $P'$, the image of $P$ on $g$.
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Answer
Since g is the reflection of f about the line y=x, the coordinates of P′(x;y) can be found by swapping the coordinates of P(4;2). Therefore, the coordinates of P′ are (2;4).
Step 2
5.2 Show that $a = 2$.
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Answer
We know that f(4)=extloga4=2. This can be rewritten as:
extloga4=2
Rearranging gives:
4=a2
Solving for a, we find:
a=2.
Step 3
5.3 Write down the equation of $g$ in the form $y = ...$
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Answer
Since g is the reflection of f(x)=extlog2x, its equation can be expressed as:
y=2x.
Step 4
5.4 $T$ is a point on $f$ in the first quadrant where $TR$ is parallel to the x-axis. Calculate the area of $ riangle ART'$.
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Answer
To find the area of riangleART′, we can use the formula for the area of a triangle: