I thawed steaks in the frige and added soy sauce to marinade them..they were in the frige for 2 days..I didn't use the steaks and so I refroze them.  Is it okay to thaw them and serve them?
I've often been told by people that I shouldn't refreeze meat (particularly hamburger meat) once it has been thawed.  However, this seems a little silly to me.  I can't imagine how meat that hasn't been bought fresh and local could find its way to my kitchen with out thawing and being refrozen a couple of times.  How much damage can one more thawing and refreezing really do?  Can it really be that dangerous disease wise? Or is this just one of those urban myths?
For the Quadratic Form $X^TAX; X\in\mathbb{R}^n, A\in\mathbb{R}^{n \times n}$ (which simplifies to $\Sigma_{i=0}^n\Sigma_{j=0}^nA_{ij}x_ix_j$), I tried to take the derivative wrt. X ($\Delta_X X^TAX$) and ended up with the following:  The $k^{th}$ element of the derivative represented as  $\Delta_{X_k}X^TAX=[\Sigma_{i=1}^n(A_{ik}x_k+A_{ki})x_i] + A_{kk}x_k(1-x_k)$  Does this result look right? Is there an alternative form?  I'm trying to get to the $\mu_0$ of Gaussian Discriminant Analysis by maximizing the log likelihood and I need to take the derivative of a Quadratic form. Either the result I mentioned above is wrong (shouldn't be because I went over my arithmetic several times) or the form I arrived at above is not the terribly useful to my problem (because I'm unable to proceed).  I can give more details about the problem or the steps I put down to arrive at the above result, but I didn't want to clutter to start off. Please let me know if more details are necessary.  Any link to related material is also much appreciated. Why is January month 0 in Java Calendar? Proof of inequality using AM-GM inequality prove that $x^2 + y^2 + z^2 \ge xy + xz + yz$  I tried proving it the way I prove $x^2 + y^2 \ge 2xy$. But it just doesn't seem to work. I tried using AM-GM. Should I be using GM-HM or AM-HM? I really don't know what the problem is and I'd appreciate any help and a full proof explanation. Thanks. Optional Methods in Java Interface Is Bran able to have children after his fall? The thing that made me ask this question was that most of Stark family are dead and Bran is now the "heir" to Winterfell. So I guess he should have children to succeed him, otherwise the Stark line will end. (I'm assuming Arya will not come back to Westeros and Rickon's fate is sealed, though I could be wrong.) I don't remember reading anything about it. Creating Logo with Fancy Font I am trying to creating a logo that resembles this one shown below, but I do not know the best way of going about it. I know of a fonts package that may be useful, but not sure how to overlay the letters on top of each as so. Would anyone know a neat way of accomplishing this?  Picture of Logo: differences between 2 JUnit Assert classes The JUnit framework contains 2 Assert classes (in different packages, obviously) and the methods on each appear to be very similar. Can anybody explain why this is?  The classes I'm referring to are:  and . Shape of a string/chain/cable/rope/wire? The height of a string in a gravitational field in 2-dimensions is bounded by $h(x_0)=h(x_l)=0$ (nails in the wall)  and also $\int_0^l ds= l$. ($h(0)=h(l)=0$, if you take $h$ as a function of arc length) .  What shape does it take?  My try so far: minimise potential energy of the whole string,  $$J(x,h, \dot{h})=\int_0^l gh(x) \rho \frac{ds}{l}=\frac{g \rho }{l}\int_0^l h(x) \sqrt{1+\dot{h}^2} dx$$  With the constraint  $$\int_0^l \sqrt{1+\dot{h}^2} dx- l=0$$ If it helps, it's evident that $\dot{h}(\frac{l}{2})=0$.  Generally, this kind of equation is a case of a constrained variational problem, meaning that the integrand in  $$\int_0^l \frac{g \rho }{l}h(x) \sqrt{1+\dot{h}^2} +\lambda(\int_0^l \sqrt{1+\dot{h}^2} dx- l)dx$$  Must satisfy the Euler Lagrange equation. The constraint must also be satisfied.  But, in truth, by this point I am clueless. $\lambda$ is worked through $\nabla J  = \lambda \nabla(\int_0^l \sqrt{1+\dot{h}^2} dx- l)$. I have tried this , but get nonsensical answers.  Is this method the best? If so, in what ways am I going about it wrongly thusfar? Preventing applications from stealing focus Are there any solutions to prevent applications stealing focus from the active window?   This is especially annoying when I'm starting an application, switch to do something else and the new application starts receiving half a sentence of text. How do I get all 3 characters together for the "Three man army" trophy? Over the course of my entire game I have been trying to phone each of the protagonists in order to get this trophy. Each time I successfully 'Hang Out' with one of the characters the other one is always unreachable (busy tone on their cell) or not interested.   What is the easiest way to get all three characters together in order to get this trophy/achievement?   Secondly, there are obviously points in the story where this is not possible due to certain characters being otherwise occupied. Is there a best or easiest time to get the characters together?  Specifically:(End game spoiler)      I want to know if it is still possible to get this trophy in post game. I choose option C: Deathwish which resulted in all three characters surviving (and becoming friends again) but I still can't get them all together? Get names of all keys in the collection I just ordered the Nvidia GTX card. I have a dilemma, though. Should I keep using the driver which is available in "additional drivers" in Ubuntu, or should I install the driver from the Nvidia site?  So which driver is the best for me? Pressing Enter should not refresh the page Why didn't the basilisk bite in Chamber of Secrets destroy the Horcrux? Show $100+t$ is reducible in $\mathbb{Z}[[t]]$ $\mathbb{Z}[[t]]$ is the ring of formal power series with integer coefficients, and the problem asks to show that $100+t$ is reducible. This means I need to find two power series, $\sum_{i=0}^\infty a_i t^i$ and $\sum_{j=0}^\infty b_j t^j$ with $a_i,b_j\in\mathbb{Z}$, that when multiplied give $100+t$. Since the integers are an integral domain, I know that neither of these power series may be finite, but I'm having a really hard time figuring out how to come up with two series that will telescope properly. Any suggestions? Wasn't the density of the universe at the moment after the Big Bang so great as to create a black hole? If the answer is that the universe/space-time can expand anyway what does it imply about what our universe looks like from the outside? Downcasting in Java Upcasting is allowed in Java, however downcasting gives a compile error.   The compile error can be removed by adding a cast but would anyway break at the runtime.   In this case why Java allows downcasting if it cannot be executed at the runtime? Is there any practical use for this concept?   public class demo {   public static void main(String a[]) {       B b = (B) new A(); // compiles with the cast,                           // but runtime exception - java.lang.ClassCastException   } }  class A {   public void draw() {     System.out.println("1");   }    public void draw1() {     System.out.println("2");   } }  class B extends A {   public void draw() {     System.out.println("3");   }   public void draw2() {     System.out.println("4");   } } Does the 14 day self-isolation period in the UK end if a travel-corridor starts during the 14-day self-isolation period? Can it be proven in $\sf ZF^{\neg\infty}$ that the sets $x_n=\{x_{n+1}\}$ do not exist? Why sum of two little "o" notation is equal little "o" notation from sum? Why sum of two little "o" notation is equal little "o" notation from sum?  $o( f(n) ) + o( g(n) ) = o( f(n) + g(n) ) ?$  For example:   $f(n) = n^3$  $g(n) = 1/n$   so    $o(f(n)) = n^2$  $o(g(n)) = 1/n^2$   and    $o( f(n) ) + o( g(n) ) = n^2 + 1/n^2$ $o( f(n) + g(n) ) = n^2$   Of course, I could write it like   $o( f(n) ) + o( g(n) ) = n^2 + o( g(n) )$ $o( f(n) + g(n) ) = n^2 + o( g(n) )$   My question is why? I don't understand it, because in first we always get two parameters.