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1.12 I: Numerical methods (A-level only)

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Question 1

f(x)=x3+2x2+x+1f(x) = x^3 + 2x^2 + x + 1f(x)=x3+2x2+x+1

a.

Show that f(x)f(x)f(x) has a root between -1.5 and -2

[3]
b.

Show that the equation f(x)=0f(x) = 0f(x)=0 can be written in the form x=−(x+1x2+2)\displaystyle x = -\left(\frac{x+1}{x^2} + 2\right)x=−(x2x+1​+2)

[3]
c.

Use the iteration formula xn+1=−(xn+1xn2+2)\displaystyle x_{n+1} = -\left(\frac{x_n+1}{x_n^2} + 2\right)xn+1​=−(xn2​xn​+1​+2) with x0=−2x_0 = -2x0​=−2 to find, to 3 decimal places, the values of x1x_1x1​, x2 x_2\,x2​ and x3x_3x3​.

[3]
d.

By choosing a suitable interval, prove that α=−1.755\alpha = -1.755α=−1.755 to 3 decimal places

[3]
Markscheme

1.12 I: Numerical methods (A-level only) Questions

  1. A Level
  2. /Maths
  3. /1.12 I: Numerical methods (A-level only)

125 exam-style questions on AQA A Level Maths 1.12 I: Numerical methods (A-level only), covering 1.12.1 Locating roots by change of sign (A-level only), 1.12.2 Iterative methods and Newton-Raphson (A-level only), 1.12.3 Numerical integration (A-level only), and 1.12.4 Numerical methods in context (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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