This may be a total newbie question, but is there a way to split an equation and save the right hand side? For example, have a look on what happens without split:

numer(L = 2/3);
"Error, invalid input: numer expects its 1st argument, x, to be of type {list, set, algebraic}, but received L = 2/3"

I thought that "convert"-function might be able to do this, but for example this does not work:

convert(L = 2/3, algebraic)

"Error, invalid input: `convert/algebraic` expects its 1st argument, pr, to be of type procedure, but received L = 2/3"

Please understand that this is a simplified example. The real problem looks like

sol := solve({eq1, eq2,eq3, res}, {L, x1, x2, x3})

The point here is how to convert the sol[1], which is L = numerator/denumerator into --> numerator/denumerator

Taking a copy of the equation works, but this is only an intermediate result, so if the split does not work automatically, Maple cannot compute the problem to the end without human intervention, and since this problem takes a long time to solve, it would be nice if I could just leave Maple to finish the task by itself.

I would like to simplify

sin(4*pi*w)/sin(2*pi*w) 

The answer I am looking for is 2*cos(2*pi*w).

Does anyone have an idea how to do this is Maple? Some earlier version of Maple I used could do this, 

simplify( sin(4*pi*w)/sin(2*pi*w) ) =  2*cos(2*pi*w)

There a plenty of different trigonometric representations for the answer, so my hypothesis is that I should somehow tell to Maple which I am looking for. 

For example

Gives

Which is better, but still not the answer I am looking for

Best Regards,

P