In die diagram hieronder is die grafiek van
f(x) = -2sin x
die interval
x ∈ [-180°; 180°]
geskets - NSC Mathematics - Question 7 - 2021 - Paper 2
Question 7
In die diagram hieronder is die grafiek van
f(x) = -2sin x
die interval
x ∈ [-180°; 180°]
geskets.
7.1 Op die rooster wat in die ANTWORLDDEBOOK verskaf word, sk... show full transcript
Worked Solution & Example Answer:In die diagram hieronder is die grafiek van
f(x) = -2sin x
die interval
x ∈ [-180°; 180°]
geskets - NSC Mathematics - Question 7 - 2021 - Paper 2
Step 1
7.1 Op die rooster wat in die ANTWORDDEBOOK verskaf word, skets die grafiek van g(x) = cos(x - 60°) vir x ∈ [-180°; 180°]. Toon duidelik ALLE snitte met die asse en die draai punte van die grafiek aan.
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Answer
To sketch the graph of
g(x) = cos(x - 60°)
for the interval
x ∈ [-180°; 180°], first determine the key features of the cosine function, including its amplitude (1), period (360°), and phase shift (60° to the right).
The turning points occur at where the cosine function reaches its maximum (1) and minimum (-1). These can be identified at:
Maximums:
x = 60°, 420° (-180° is at the start of the interval, thus wrapping back)
Minimums:
x = -120°
Additionally, the x-intercepts occur where
g(x) = 0
depicting the points
x = -30°
&
x = 150°.
Mark these points and ensure to include a smooth transition in the sketch.
Step 2
7.2 Skryf die periode van f(3x) neer.
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Answer
The period of the function
f(kx)
can be calculated using the formula:
extPeriod=k360°
For (3x)
, where k = 3, the period becomes:
extPeriod=3360°=120°.
Thus, the period of (3x)
is 120°.
Step 3
7.3 Gebruik die grafieke om die waarde van x in die interval x ∈ [-180°; 180°] te bepaal waarvoor f(x) - g(x) = 0.
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Answer
To find the values of x for which
f(x) - g(x) = 0,
we assess the intersecting points of both graphs obtained in the prior steps. From the sketch, the graph illustrates that the intersections are at:
x = -30°,
which corresponds to both functions equating at this angle within the defined interval.
Step 4
7.4 Skryf die waardeverzameling van k neer, k(x) = rac{1}{2}g(x) + 1.
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Answer
Firstly, identify the range of
g(x) = cos(x - 60°
which is ext{[-1, 1]}.
Through transformation of the function with
y = rac{1}{2}g(x) + 1
the following adjustments occur:
The amplitude transformation is halved, which changes the range to ext{[-0.5, 0.5]}.
Adding 1 shifts the entire range upward by 1, resulting in:
Range of
k(x)
becomes: