Re: Simple equation checking..

*To*: mathgroup at smc.vnet.net*Subject*: [mg25665] Re: Simple equation checking..*From*: "Bill Bertram" <wkb at ansto.gov.au>*Date*: Wed, 18 Oct 2000 02:52:34 -0400 (EDT)*Organization*: Australian Nuclear Science and Technology Organisation*References*: <8seb1e$6tb@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Ian Fan <ian at v-wave.com> wrote in message news:8seb1e$6tb at smc.vnet.net... > > Hi again, thanks for all the help with my last question but now I am stuck > with another problem if anyone would be so kind enough to help. > > I am looking for a way to check equations, for example, the derivative of > ((x^3 - 4x + 3)/x^(4/3) is (5x^(10/3) - 8x^(7/3) - 12x^(1/3))/(3x^(8/3)) > when calculated via hand but is (3x^2 - 4)/x^(4/3) - 4(x^3 - 4x + > 3)/(3x^(7/3)) when put through mathematica. Simply use the A == B statement to check for true or false! For your example Mathematica will only return a true/false result if the statement is actually true for all values of x. If the statement is not true in general it may well be true for certain values of x so Mathematica does cannot give the result "false". > What I would like to do is if > there is any way to equate the two and see if the statement is true because > obviously it can look like two completely different answers (to a student) > when they are in fact the same. ...but the two expressions you have given above, are not the same! Try evaluating them with x=1. > Another example would be, is there any way to check if E^(:ii:Pi) = -1 was > true (at least according to the Euler-Moivre equation), using Mathematica? Yes, E^(:ii:Pi) == -1 gives the result "true" Cheers, Bill