Int gives wrong answer

syms x
f(x) = cos(x)*sin(x);
Fx = int(f,x)

Fx(x) = 

Fx(x) =

sin(x)^2/2

while the correct answer is -cos(x)^2/2

[Robin Merkle]

The answer is correct. d/dx sin^2(x)/2 = sin(x)cos(x).

[Torsten]

Since sin(x)^2/2 = -cos(x)^2/2 + 1/2, both answers are correct.

Note that both answers only differ by a constant, namely 1/2.

[Ali M]

Thanks @Torsten & @Robin Merkle! @Torsten I would vote for you but I cant, your is a comment not an answer

Answer 1

[Walter Roberson]

Remember that indefinite integration always has an implied "plus a constant". So any two results of int() that differ by a constant are the same integral result. And sin squared plus cos squared equals 1 so the two possibilities are the same up to the constant.

You can ask to rewrite() to 'cos'