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1.8 Integration

1.8 Integration

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Question 93

The cross-section of a parabolic archway is modeled by the curve C C\,C with equation y=6x−x2y = 6x - x^2y=6x−x2, where y y\,y is the vertical height in metres and x x\,x is the horizontal distance from the left-hand base O O\,O at the origin. A straight support strut L L\,L is to be installed from the origin to a point Q Q\,Q on the archway. The strut follows the equation y=kxy = kxy=kx, where k k\,k is a constant and 0<k<60 < k < 60<k<6.

a.

Find, in terms of kkk, the coordinates of QQQ.

[2]
b.

The region R1 R_1\,R1​ is the area of the archway cross-section that lies above the support strut and below the curve CCC.

Show that the area of R1 R_1\,R1​ is

(6−k)36 \frac{(6 - k)^3}{6} 6(6−k)3​
[4]
c.

The region R2 R_2\,R2​ is the area of the archway cross-section that lies below the support strut, above the horizontal ground (xxx-axis), and is bounded to the right by the archway.

Given that the area of R1 R_1\,R1​ is equal to the area of R2R_2R2​, find the exact value of kkk.

[4]
Markscheme

1.8 Integration Questions

  1. A Level
  2. /Maths
  3. /1.8 Integration

160 exam-style questions on WJEC A Level Maths 1.8 Integration, covering 1.8.1 Integration, 1.8.2 Integration, and 1.8.3 Integration. Each one has a worked solution and a mark scheme showing where the marks go.

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