function reacts differently if value passed in as variable and not hard coded

Ok, i have a function that is moving a mc in a spiral.

Here is the code:

Code:

---

//rotz(dot, 300, 300, .1, 1.004);
rotz(dot, origin_1_x, origin_1_y, .1, 1.004);

function rotz(who,cx,cy,spd,exp){
        trace("first x "+who._x);
        trace("cx "+cx);
        dx = (who._x -cx) * exp;
        dy = (who._y -cy) * exp;
        trace("dy "+dy);
        trace("equation " +(cx+((Math.cos(spd) * dx -(Math.sin(spd) * dy)))));
        who._x = cx+((Math.cos(spd) * dx -(Math.sin(spd) * dy)));
        who._y = cy+((Math.sin(spd) * dx +(Math.cos(spd) * dy)));
        trace("second x "+who._x);
}

---

right now i have origin_1_x set to 300, so it should act the same as if i had 300 hardcoded (which is currently commented out).

When I hard code 300 in there it works great. but since i will let the user decide what the origin will be, i want to pass a variable instead.

currently, when i hardcode 300 in this is my trace output:

first x 246.95
cx 300
dy -66.3644
equation 253.629273943845
second x 253.6

However, when i pass the variable instead, this is my output

first x 246.95
cx 300
dy -66.3644
equation 300-46.3707260561545
second x 246.95

x gets passed in just fine (as cx is 300), however, the assignment of changing the value of who._x doesn't work at all. and the equation brings back a different result...

anyone else encounter something like this before?

any ideas?

thanks
ty

ok, i'm more awake and capable of debugging now, but i am still having problems.

for some reason the variable cx is not getting interpreted

who._x = cx+((Math.cos(spd) * dx -(Math.sin(spd) * dy)));

This comes back

300-46.3707260561545

I've even played with it some like so:

Code:

---

tempVar = Math.cos(spd) * dx -(Math.sin(spd) * dy);
trace("temp "+tempVar);
trace("cx "+cx);
tempVar + = cx;
trace("new temp" + tempVar);

---

this returns:

temp -46.3707260561545
cx 300
new temp-46.3707260561545300

Yet, if i change the line
tempVar += cx;
to
tempVar += 300;


then this works fine

i'm really not sure why it's not interpreting cx correctly. And like i said in the first post, when i pass in hardcoded numbers this works fine. but even if i pass in a variable equal to 300 it seems to cause this mess.

anyone have any ideas? i'm really confused.

-ty