IB Prized Writing Sevenoaks School IB Prized Writing 2014 | Page 116

Nina del Ser - Mathematics octopus | figure 9: Ω4 figure 10: Ω9 figure 11: Ω1 figure 12: Ω22 11 Secondary rotor spins clockwise Here are curves with corresponding values of Ω, only this time they are negative. An exception was made for figure 15 because Ω=-1 would have simply repeated one of the simple cases discussed above. figure 13: Ω4 figure 14: Ω9 figure 15: Ω3 figure 16: Ω22 Closer inspection shows that the curves all seem to be following a trend: the number of axes of symmetry in any given curve is defined by the angular speed of the secondary rotor (e.g the curve generated when Ω9 shows rotational symmetry of order 9). What follows is a simple mathematical explanation for this behaviour. Square and add together the x and y components in equation (5) to obtain an expression for r 2 : 115