Sketch the graphs of y=lnxy = \ln xy=lnx and y=12x\displaystyle y = \frac{1}{2x}y=2x1 for x>0 x > 0\,x>0 on the same axes.

Explain why the equation lnx=12x\displaystyle \ln x = \frac{1}{2x}lnx=2x1 has exactly one solution.
By considering a suitable change of sign, show that the solution to the equation lies between 1.4 and 1.5
Use the iterative formula xn+1=e12xn\displaystyle x_{n+1} = e^{\frac{1}{2x_n}}xn+1=e2xn1 with x1=1.5x_1 = 1.5x1=1.5, to find x2,x3 x_2, x_3\,x2,x3 and x4x_4x4, giving your answers to four decimal places.
329 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.