Skip to content

Course home

Numerical Methods

Numerical Methods

MediumHard
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576
Question 48

The function f f\,f is defined by f(x)=exx−1f(x) = e^x \sqrt{x} - 1f(x)=exx​−1

a.

f(x)=0f(x) = 0f(x)=0 has a single solution at the point x=αx = \alphax=α. By considering a suitable change of sign, show that α \alpha\,α lies between 0 and 1

[2]
b.

Show that f′(x)=ex(2x+1)2x\displaystyle f'(x) = \frac{e^x(2x + 1)}{2\sqrt{x}}f′(x)=2x​ex(2x+1)​

[3]
c.

Use the Newton-Raphson method with x1=1x_1 = 1x1​=1 to find x3x_3x3​, an approximation for α\alphaα. Give your answer to five decimal places

[2]
d.

Explain why the Newton-Raphson method fails to find α \alpha\,α with x1=0x_1 = 0x1​=0

[2]
Markscheme

Numerical Methods Questions

  1. A Level
  2. /Maths
  3. /Numerical Methods

80 exam-style questions on Edexcel A Level Maths Numerical Methods, covering 10.1 Locating Roots, 10.2 Iteration, 10.3 The Newton-Raphson Method, and 10.4 Applications to Modelling. Each one has a worked solution and a mark scheme showing where the marks go.

Question bank