MaplePrimes - answers and comments on Question, simplify/combine doesn't see power?

By symbolic

Markiyan Hirnyk — Fri, 18 Nov 2011 23:22:51 Z

I think it was asked a lot.

>simplify(GAL,symbolic);

or using assumptions

Axel Vogt — Sat, 19 Nov 2011 00:04:41 Z

combine(GAL, radical) assuming x::real;

Simplify weakness

Robert Israel — Sat, 19 Nov 2011 00:08:51 Z

While Markiyan is right that simplify(..., symbolic) works, that shouldn't be necessary here: this simplification should be valid for all complex numbers x (except, of course, the square roots of -3/2). If it were not always valid, appropriate assumptions should work; but in this case I can't get anything of the form
simplify(..) assuming ... to work. Note that if the sqrt(4*x^2+6) was replaced by sqrt(2)*sqrt(2*x^2+3), the expression would automatically be simplified to

and simplify would do the rest.

I'll submit an SCR.

Thanks

icegood — Sat, 19 Nov 2011 02:56:52 Z

Thanks for all of you.

symbolic is irrelevant

Alejandro Jakubi — Mon, 21 Nov 2011 05:05:44 Z

The routine that actually makes the relevant transformation is `simplify/sqrt/fraction`. And the piece of code responsible for it is executed when there is a second argument, it may be symbolic or whatever, it doesn't matter:

`simplify/sqrt/fraction`(GAL,kk);
                                       1/2
                                    3 3
                                 -------------
                                     2     3/2
                                 (2 x  + 3)

In my opinion, a big problem with simplify is that the specification of the simplification rules is generically missing. So, deciding what is a bug for it becomes largely a subjective issue.