#3155 is(abs(cos(x))<=1) is unknown, but is(cos(x)<=1) and is(cos(x)>=-1) are true

[David Scherfgen]

(%i1) is(cos(x)<=1);
(%o1) true
(%i2) is(cos(x)>=-1);
(%o2) true
(%i3) is(abs(cos(x))<=1);
(%o3) unknown

[David Scherfgen]

Maybe inequalities involving abs(f(x)) can be reduced to f(x)^2, which is already handled correctly.

[David Scherfgen]

Fixed by commit [96ea42].