The point P divides the interval from A(−4, −4) to B(1, 6) internally in the ratio 2:3 - HSC - SSCE Mathematics Extension 1 - Question 11 - 2017 - Paper 1
Question 11
The point P divides the interval from A(−4, −4) to B(1, 6) internally in the ratio 2:3.
Find the x-coordinate of P.
(b) Differentiate tan⁻¹(x³).
(c) Solve 2x/(x +... show full transcript
Worked Solution & Example Answer:The point P divides the interval from A(−4, −4) to B(1, 6) internally in the ratio 2:3 - HSC - SSCE Mathematics Extension 1 - Question 11 - 2017 - Paper 1
Step 1
Find the x-coordinate of P.
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Answer
To find the x-coordinate of point P, we use the section formula for internal division. The coordinates of A are (-4, -4) and B are (1, 6). The ratio is 2:3, which means:
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Answer
Let ( y = \tan^{-1}(x^3) ).
Using the chain rule, the derivative is:
dxdy=1+(x3)21⋅3x2=1+x63x2.
Step 3
Solve 2x/(x + 1) > 1.
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Answer
To solve the inequality:
Multiply both sides by (x + 1) (noting that this changes the inequality if x + 1 < 0):
2x>x+1.
Rearranging gives us:
2x−x>1⟹x>1.
Consider the case when (x + 1) < 0, so ( x < -1 ):
2x<x+1⟹x<1.
Therefore, the solution is:
x>1 or x<−1.
Step 4
Sketch the graph of the function y = 2 cos⁻¹(x).
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Answer
The graph of ( y = 2 \cos^{-1}(x) ) is between the points x = -1 and x = 1. The range of y is between 0 and 2π. At x = -1, y = 2π and at x = 1, y = 0. The graph is a decreasing function, falling from (0, 2π) to (1, 0), creating a concave shape.
Step 5
Evaluate \( \int_{0}^{3} \frac{x}{\sqrt{x + 1}} \, dx \), using the substitution x = u² − 1.
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Answer
Let ( x = u^2 - 1 ) then ( dx = 2u , du. )
The limits change: when x = 0, u = 1, and when x = 3, u = 2.
Substitute into the integral:
∫12u2u2−1(2udu)=2∫12(u2−1)du=2[3u3−u]12.
Calculate:
=2(38−2−(31−1))=2(38−6+1)=2(33)=2.
Step 6
Find \( \int \sin^{2}(x) \, \cos(x) \, dx. \)
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Answer
Using the substitution ( u = \sin(x), ; du = \cos(x) , dx. )
The integral becomes:
∫u2du=3u3+C=3sin3(x)+C.
Step 7
Write an expression for the probability that exactly three of the eight seedlings produce red flowers.
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Answer
Let ( p = \frac{1}{5} ) and ( q = \frac{4}{5} ). The required probability is given by the binomial formula:
P(X=3)=(38)p3q5=(38)(51)3(54)5.
Step 8
Write an expression for the probability that none of the eight seedlings produces red flowers.
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Answer
The probability that none produces red flowers is given by:
P(X=0)=(08)p0q8=(54)8.
Step 9
Write an expression for the probability that at least one of the eight seedlings produces red flowers.
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Answer
The probability that at least one seedling produces red flowers is the complement of none: