The points A, B and C lie on a circle with centre O, as shown in the diagram - HSC - SSCE Mathematics Extension 1 - Question 12 - 2017 - Paper 1
Question 12
The points A, B and C lie on a circle with centre O, as shown in the diagram.
The size of \( \angle ZAOC \) is 100°.
Find the size of \( \angle ZABC \), giving reas... show full transcript
Worked Solution & Example Answer:The points A, B and C lie on a circle with centre O, as shown in the diagram - HSC - SSCE Mathematics Extension 1 - Question 12 - 2017 - Paper 1
Step 1
Find the size of \( \angle ZABC \), giving reasons.
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Answer
To find the angle ( \angle ZABC ), we can use the property that the angle at the circumference is half the angle at the center when both angles subtend the same arc.
Given that ( \angle ZOAC = 100° ), we first find the reflex angle ( \angle ZAO = 360° - 100° = 260° ).
Using the relationship:
∠ABC=21reflex ∠ZAO=21(260°)=130°.
Therefore, ( \angle ZABC = 130° ).
Step 2
Carefully sketch the graphs of \( y = |x + 1| \) and \( y = 3 - |x - 2| \) on the same axes, showing all intercepts.
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Answer
The graph of ( y = |x + 1| ) will have a V-shape with the vertex at ( (-1,0) ).
The graph of ( y = 3 - |x - 2| ) will also have a V-shape with the vertex at ( (2, 3) ) and intercepts at ( (1, 2) ) and ( (3, 0) ).
Ensure the x-values are clearly marked and the y-intercepts are labeled correctly.
Step 3
Using the graphs from part (i), or otherwise, find the range of values of \( x \) for which \( |x + 1| + |x - 2| = 3. \)
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To find the range, we solve the equation:
For ( x < -1 ): ( -(x + 1) + (2 - x) = 3 ) leads to no solution.
For ( -1 \leq x < 2 ): ( (x + 1) + (2 - x) = 3 ), leads to the range ( x = -1 ).
For ( x \geq 2 ): ( (x + 1) + (x - 2) = 3 ) translates to ( 2x - 1 = 3 ), yielding ( x = 2 ).
Thus, the range of ( x ) is ( -1 \leq x ext{ or } x = 2. )
Step 4
Show that \( h \) satisfies the equation \( 3h^3 - 9h + 2 = 0. \)
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Answer
To demonstrate this,
The volume of the first solid formed by the semicircle is given by:
V1=π∫0h(1−x2)2dx=π∫0h(1−x2)dx=π[x−3x3]0h=π(h−3h3).
The volume of the second solid formed by the remaining area is:
V2=π∫h1(1−x2)2dx=π(2π−V1).
Setting the volumes ratio to 2:1 will lead to:
V2V1=21⇒ultimately giving the equation 3h3−9h+2=0.
Step 5
Given \( h_1 = 0 \) as the first approximation for \( h \), use one application of Newton's method to find a second approximation for \( h. \)
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Answer
To apply Newton's method:
Compute the function:
f(h)=3h3−9h+2
with ( f(0) = 2. )
Find the derivative:
f′(h)=9h2−9.
Calculate:
h2=h1−f′(h1)f(h1)=0−−92=92.
Therefore, the approximation for ( h ) would be rendered as ( h_2 = \frac{2}{9}. )
Step 6
Find the acceleration of the particle as a function of t.
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To find the acceleration, we first differentiate the displacement with respect to time:
( x = 4 - e^{-2t} )
Taking the first derivative:
dtdx=2e−2t
The acceleration, which is the second derivative:
dt2d2x=−4e−2t. \nHence, the acceleration of the particle as a function of ( t ) is given by ( -4e^{-2t}. )