# royston

Most popular questions and responses by royston-
## mechanics (calculating plane speed and climb angle

Two radar stations A and B, are separated by the distance a = 500 m, track the plane C by recording the angles α and β at 1-second intervals. If three successive readings are t (s) 9 10 11 α 54.80◦ 54.06◦ 53.34◦ β 65.59◦ 64.59◦ 63.62◦

*asked on November 10, 2012* -
## computing/maths

Derive the central difference approximation for f′′(x) accurate to O(h4) by applying Richardson extrapolation to the central difference approximation of O(h2). (Note that f''(x)= 2nd derivative of x)

*asked on November 11, 2012*