The equation has an odd number of solutions
Source: Vietnam TST 1985 Problem 5
February 5, 2010
trigonometryfunctionalgebra proposedalgebra
Problem Statement
Find all real values of a for which the equation (a \minus{} 3x^2 \plus{} \cos \frac {9\pi x}{2})\sqrt {3 \minus{} ax} \equal{} 0 has an odd number of solutions in the interval [ \minus{} 1,5]