In the diagram below, the graphs of $f(x) = an x$ and $g(x) = 2 ext{sin} 2x$ are drawn for the interval $x ext{ in } [-180^ ext{o}; 180^ ext{o}]$ - NSC Mathematics - Question 6 - 2022 - Paper 2
Question 6
In the diagram below, the graphs of $f(x) = an x$ and $g(x) = 2 ext{sin} 2x$ are drawn for the interval $x ext{ in } [-180^ ext{o}; 180^ ext{o}]$. A(60^ ext{o}; k)... show full transcript
Worked Solution & Example Answer:In the diagram below, the graphs of $f(x) = an x$ and $g(x) = 2 ext{sin} 2x$ are drawn for the interval $x ext{ in } [-180^ ext{o}; 180^ ext{o}]$ - NSC Mathematics - Question 6 - 2022 - Paper 2
Step 1
Write down the period of g.
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Answer
The period of g(x)=2extsin2x is given by the formula:
ext{Period} = rac{2 ext{π}}{b} where b is the coefficient of x. In this case, b=2, so the period is:
ext{Period} = rac{2 ext{π}}{2} = ext{π} ext{ or } 180^ ext{o}.
Step 2
Calculate the value of k.
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Answer
To find the value of k at the point A where x=60exto, we substitute x=60exto into the equation of g(x):
g(60^ ext{o}) = 2 ext{sin}(2 imes 60^ ext{o}) = 2 ext{sin}(120^ ext{o}) = 2 imes rac{ ext{√3}}{2} = ext{√3}. Thus, k=ext√3extorapproximately1.73.
Step 3
Coordinates of B.
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Answer
The coordinates of point B can be determined from the intersection points. From the graph and the interval, we determine:
B(−120exto;−ext√3).
Step 4
Write down the range of 2g(x).
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Answer
The range of g(x) is [−2;2]. Thus, the range of 2g(x) is:
[−4;4].
Step 5
For which values of x will g(x + 59°) – f(x + 59°) ≤ 0 in the interval x ∈ [-90°; 0°]?
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Answer
To solve for x where g(x+59exto)−f(x+59exto)ext≤0, we analyze the functions within the interval:
−65exto≤x≤−5exto.
Step 6
Determine the values of p for which sin x cos x = p will have exactly two real roots in the interval x ∈ [-180°; 180°].
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Answer
We start from the equation:
extsinxextcosx=p
Using the identity, we get:
rac{1}{2} ext{sin}(2x) = p. For this to have exactly two real roots in the given interval, we find the values of p such that:
p = rac{1}{2} ext{ or } -rac{1}{2}.