1.2.6 Helper function. Used by Second special case

#solves x y' = c x^n + a y - b y^2 THEN 
riccati_special_i :=proc (a,b,c,n,y,x) 
 
    -- note sign difference from book, typo in book. 
    IF bc>0 
        SOL:= y = SQRT(c/b) x^a tanh(C + SQRT(bc) x^2/a) 
    ELIF bc<0 THEN 
        SOL:= y = SQRT(-c/b) x^a tan(C + SQRT(-bc) x^2/a) 
    END IF 
 
    RETURN(SOL) 
end proc