HP Prime Android and PC emulator give wrong answer for simplify((sin(3*x)+sin(7*x))/sin(5*x)

[Corruptissima]

The simplify((sin(3*x)+sin(7*x))/sin(5*x)) answers given by both PC Prime enulator and Prime Pro version on Android give wrong answer of 

2*COS(2*x) instead of 4*(cos(x))^2-2. Both the PC and Andriod verion has Software version: 2.1.14181.

Does this happen to an actual Prime handheld version? I'm testing the Emulator version before deciding to buy the physical one. 

[Tim_Wessman]

What makes you think that is an incorrect result? 😄

https://www.wolframalpha.com/input/?i=simplify((sin(3*x)%2Bsin(7*x))%2Fsin(5*x))

[Corruptissima]

Thanks, Tim for your reply.

The reason was that one of the documents I came across called  "Symbolic computation and Mathematics with
the calculator HP Prime.  Shows that simplify((sin(3*x)+sin(7*x))/sin(5*x))
We get:
4*(cos(x))^2-2 and When I checked on GeoGebra Cas Program it also showed the same answer.

Thanks once again for your reply.

[Tim_Wessman]

Well, both are equivalent.