||'''Book'''|| Advanced Engineering Mathematics ||
 ||'''Author'''|| Erwin Kreyszig ||
 ||'''Edition'''|| 8th Edition ||

/* code_begins */

{{{

x = var('x')
y = var('y')
#a)
contour_plot(x^3 - 3*x*y^2, (x, -500, 500), (y, -500,500))
#b)
contour_plot(3*x^2*y - y^3, (x, -500, 500), (y, -500,500))
#c)
contour_plot(cos(x)*cosh(y), (x, -100, 100), (y, -100,100))
#d)
contour_plot(sin(x)*cosh(x), (x, -500, 500), (y, -500,500))
#e)

contour_plot(log((x - 1)^2 + y^2,e), (x, -500, 500), (y, -500,500))
#f)

contour_plot(cos(x)^2 + sinh(y)^2, (x, -500, 500), (y, -500,500))}}}

/* code_ends */

 * '''Solution by''': 
  * ganesh, developer, space
  * bhanukiran, student, technical university of Delft
  * saransh, student, sobhit university