20. let s be the family of ortnog k> 0.if cesand c passes through the pom (a) (4-y2) (b) (2,-4) (c) (2,2 v2) 21. letx, x+e" and 1+x+ 0" be solutions of a linear

20. Let S be the family of ortnog k> 0.If CeSand C passes through the pom (a) (4-y2) (b) (2,-4) (c) (2,2 v2) 21. Letx, x+e" and 1+X+ 0" be solutions of a linear second order ordinary differentiol with constant coeficients. If y(x) is the solution of the same equation satisfying v(O) a a ond order ordinary differential equation and Y(0)=4, then y() is equal to (a) e +1 (b) 2e+3 (c) 3e +2 (d) 3e+1 22 The function (x, y)= X +2xy +y°has a saddle point at