mathematics - Circular Bullet Spread Is Not Even

I'm creating a bullet shooter much in the style of Touhou. Right now I want to have a very simple circular shot being fired from the enemy.

However, the spacing is very uneven, which isn't very good if you want to survive.

The code I'm using is this:

private function shoot() : void
{

    const BULLETS_PER_WAVE : int = 72;
    var interval : Number = BULLETS_PER_WAVE / 360;

    for (var i : int = 0; i < BULLETS_PER_WAVE; ++i)
    {
        var xSpeed : Number = GameConstants.BULLET_NORMAL_SPEED_X * Math.sin(i * interval);
        var ySpeed : Number = GameConstants.BULLET_NORMAL_SPEED_Y * Math.cos(i * interval);

        BulletFactory.createNormalBullet(bulletColor_, alice_.center, xSpeed, ySpeed);
    }


    canShoot_ = false;
    cooldownTimer_.start();
}

I imagine my mistake is in the sin & cos functions, but I'm not entirely sure what's wrong.

Answer

Golden rule when working with any kind of angle: Make sure you are using the correct unit. In this case, you should be using radians, not degrees.

Math.sin(i * interval * Math.PI / 180);
Math.cos(i * interval * Math.PI / 180);

If you want to fire bullets directly between boss and player, use atan2, FYI.