Find all the singular points of the following ODEs and determine whether each one is regular or irregular. If the singular point is regular, determine the indicial equation and determine a lower bound for the radius of convergence of the Frobenius series. You must not try to compute the series solution itself. (x - 2)y" + xy + cot(x)y = 0. b. sinh?(r)g +(1 cosh(r))! +ry=0. c. (3x +4)y" + xy' + y =0. d. 2xy"+y' - 3xy = 0.