||'''Book'''|| Linear Algebra ||
 ||'''Author'''|| Gilbert Strang ||
 ||'''Edition'''||  ||

/* code_begins */

{{{
var('x,y')
f=function('f',x,y)
f=2*x**2+4*x*y+y**2;f
F=diff(f,x);F
F(1,-1)
print "f and F  are not positive definite"
}}}

/* code_ends */

 * '''Solution by''': 
   * <sarada>, <student>, <prakasam>
   * <ananthalakshmi>, <student>, <prakasam>