Recent content by torquerotates

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    Conditional Epectation of Multinomial

    Interesting. Makes sense. Well, E(X1,X2) is just expectation of x1 and x2
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    Showing Chi squared is independent with another variable

    So I have X1 and X2 are iid standard normal. Then I have Y=X1^2+ X2^2 and Z=X1/(X1^2+x2^2) I'm supposed to find the distribution of Y and Z and then determine if they are independent. Clearly Y is chi squared with degrees of freedom 2. But I have no idea how to find the distribution of Z...
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    Conditional Epectation of Multinomial

    So I'm trying to find E(X1,X2|Xn) where X1,X2,...Xn are the numbers of cell observations in a multinomial distribution. How do I even calculate this? I know it is not independent so I cannot split it. Does it have something to do with the fact that E(Xi)=nPi ?
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    Odd, Even, or Neither: Combining Functions in Algebra

    Thanks, I was tired, f(-x)=-f(x) for odd. product(-x)=e(-x)o(-x)=(e(x))(-o(x))=-e(x)o(x)=-product(x) =>product(x) is odd quotient(-x)=e(-x)/o(-x)=e(x)/(-o(x))=-e(x)/o(x)=-quotient(x) => quotient(x) is odd. The sum and difference gives us neither. There is nothing that can give an even.
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    Odd, Even, or Neither: Combining Functions in Algebra

    Homework Statement Consider two functions, either of which is even or odd. But neither is neither even nor odd. Determine which algebraic combinations(sum, difference, quotient, product) of the given functions will result in an odd function, an even function, and in a function that is...
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    How to make a video like this on a Mac

    Now this guy makes a video very similar to how Khan Academy would. But the difference is that he can actually put well printed equations( maybe latex) into it as well as circle things to monentarely highlight while not having to erase. So, any idea what software he uses? Is this even...
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    Best Time to Learn Critical Thinking Skills

    Now, I'm aware that the best time to learn a new language it during your toddler years. This got me thinking. What if the best time to learn logical thinking is also during this time? I know for a fact that kids are not taught critical thinking skills. I tutored many kids and only see them do...
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    Using info from g' and g'' to find answer

    Homework Statement Let g be a twice differentiable function with g'(x)>0 and g''(x)>0 for all x. g(4)=12 and g(5)=18. Which is a possible value for g(6)? a)15 b)18 c)21 d)24 e)27 Homework Equations slope=change y/ change x The Attempt at a Solution Ok so [g(5)-g(4)]/1=6 a-c...
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    Best Way to Prep For a Perfect GRE Math Section Score

    Physic_UG. What source did you use? Did you skip the easy problems or did you do them all?
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    Best Way to Prep For a Perfect GRE Math Section Score

    Statistics. But I still want to get a perfect score since I might be tutor for gre/sat math.
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    Best Way to Prep For a Perfect GRE Math Section Score

    Ok so I have a degree in math. I'm pretty sure I'll get above average on the GRE math section. But I want to get a perfect. What are the best sources to get a perfect score? I tried reading princeton review, but they mostly give me common sense type questions. Are there any books that gives me a...
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    Dynamic Math Software for Online Tutoring

    I'm thinking about doing online tutoring. I already know how to use latex on a website but I need to be much faster for a live tutorial session. Is there a way that I can write my math down on a tablet and have it automatically converted in rich math text and also have it automatically...
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    C/C++ [C++] Declaring an array within a loop

    The following code block is in C++ Everything is inside the first for loop. for( int i=0; i<=2; i++) { int a[3]={0}; for(int j=0; j<3; j++) a[i]=j; for( int i=0; i<=2; i++) cout<<a[i]; cout<<endl; } basically I am trying to get the screen to output...
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    Confused about logical statements.

    A and B or C Does that even makes sense as a statement? I thought logical operators are binary. Obviously, the "or" links to C but what is on the other side? A or B? i mean 1+2-3=0 makes sense since (1+2)-3=3-3=0=1-1=1+(2-3) But [(A and B) or C]=(AorC)and(BorC) [ A and (...
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