0
$\begingroup$

I have this expression

Simplify[2 wb Z - 2 w xiR^4 Zb - 
  2 xiR^2 Sqrt[(wb Z - w xiR^4 Zb)^2/xiR^4]]

which is actually zero when just calculated by hand, with no assumptions needed...

But Simplify just give the expression back within the brackets. Why is this?

Here in my case, xiR, w, wb, Z and Zb are complex-valued, A is real.

$\endgroup$
1
  • 3
    $\begingroup$ There is an implicit assumption you've made. In particular, your simplification relies on xiR \[Element] Reals and an assumption about the positivity of (wb Z - w xiR^4 Zb). $\endgroup$
    – evanb
    Commented Apr 28, 2015 at 17:45

1 Answer 1

4
$\begingroup$
Simplify[PowerExpand[
  2 wb Z - 2 w xiR^4 Zb - 2 xiR^2 Sqrt[(wb Z - w xiR^4 Zb)^2/xiR^4]]]

(*0*)
$\endgroup$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.