The indicial equation of the DE 2x(x+2)y"+y'-xy=0 when x=0 is a) r² (4-3)=0 b) r² (4-r)=0 c) r(4-3)=0 d) 4r-3=0 The singular points of the DE x(1-x²)' " + (1-x²)² y' + 2(1+x) y = 0 are 0, 1, and −1. The singular point 1 is a) a regular singular point b) an irregular singular point c) saddle point d) None of the above The Laplace transform of the function f(t)=e cos bt is S a) 5²+b² b b) s²+b² 2bs c) s²+b² s-a d) (s-a)²+b² The inverse Laplace transform of the function F(s) = b) y(t)=2e cost+3e' sint c) y(t)=2e+3e² d) y(t)=2e cost 2s+1 is