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"You have enemies? Good. That means you've stood up for something, sometime in your life" - Winston Churchill


May
14
answered solving Differential Equation
May
14
comment What is the geometrical representation of $1/R$?
@Patrick, I envy you (blackboard at home?) My +1
May
14
comment Mathmatical representation of recursion function
Your $foo(n)$ is a flat function with value $1$, unless you are going to change your question to something else later.
May
14
comment Mathmatical representation of recursion function
How is your answer helping this question?
May
14
comment Mathmatical representation of recursion function
$f(1) =f(0)+f(-2)-1 = 1+1-1 = 1, f(2)=f(1)+f(-1)-1=1. f(3)=f(2)+f(0)-1=1$
May
13
comment elementary inequality proof
Use $\frac{5a+b}{2} \geq \sqrt{5ab}$ and also the fact that $\sqrt{5} > 2$ to get the desired result.
May
13
comment Triangle-ish Number Series
$T$ is not the same in those two expressions, and if they are then $q=x-(n+1)y$
May
13
comment Multiplication convention rules
The fact that students have to face such a teacher year after year, I would give a warning (if I come across such grading) and the second such mistake would cause termination.
May
13
comment How to multiply two polynomials represented by values at distinct points?
Computationally if you store them as a vector, that is equivalent to what J.D. has answered. (If one has written a program in any language one would know)
May
12
comment Help with question involving limits, bounds, inequalities
$(4+5)^n > (4^n+5^n)$ and try similarly from the other end to show $(a)$ part.
May
12
answered How to multiply two polynomials represented by values at distinct points?
May
12
comment How to multiply two polynomials represented by values at distinct points?
You treat them like vector implementation (not matrices). You would have for polynomials of degree $n$, $n$ multiplications and $n-1$ addition for product.
May
12
comment Sum from 0 to n of $ n \choose i $?
MSE ought to incorporate some AI techniques to catch duplicate questions automatically.
May
12
comment Sum from 0 to n of $ n \choose i $?
Always google search and wiki search. Induction proof at proofwiki.org/wiki/Sum_of_Binomial_Coefficients_for_Given_n
May
12
revised Sum from 0 to n of $ n \choose i $?
edited body
May
11
comment Contemporary mathematician one should know about
Manjul Bhargava(Harvard),Kiran Kedlaya(MIT),Soundararajan(Stanford), Ravi Vakil(Stanford)
May
10
comment What is the $\sum\limits_{i=0}^{\ (\log_2(n))-1)}\frac{n}{2^i}$?
I did not see that (Oops!..You have already mentioned that)
May
10
comment What is the $\sum\limits_{i=0}^{\ (\log_2(n))-1)}\frac{n}{2^i}$?
Technically $log_2 (n)$ may not give integer value. Therefore it makes sense to use the floor function, i.e. instead of $m-1$, use $\left \lfloor log_2 n - 1\right \rfloor$
May
10
comment Factoring a number to get an encoded string
Decoding algorithms in general has to work both ways (left to right or right to left). Instead of re-inventing a new algorithm one could also use Base-32. (stackoverflow.com/questions/641361/base32-decoding)
May
8
comment solving ODE using variation of parameters
First find the solution to the corresponding homogeneous equation $y\prime\prime+y\prime-2y=0$ by using characteristic equation $r^2+r-2=0$