Alfred Chern

Unregistered less info
962 reputation
14
bio website
location Beijing, China
age 23
visits member for 1 year, 6 months
seen Jan 17 '13 at 14:33

Sep
27
awarded  Yearling
Oct
10
answered Comparison of differential inequalities
Oct
10
answered Solve $5a^2 - 4ab - b^2 + 9 = 0$, $ - 21a^2 - 10ab + 40a - b^2 + 8b - 12 = 0$
Oct
10
answered Prove by induction $\sum_{i=1}^ni^3=\frac{n^2(n+1)^2}{4}$ for $n\ge1$
Oct
9
revised An inequality on trace of product of two matrices
added 453 characters in body
Oct
9
answered An inequality on trace of product of two matrices
Oct
9
answered Simplify sum using a combinatorial identity
Oct
9
comment The double partial derivative
@dexterity: Because $f_{xy}=(f_{x})_{y}$, it should derivate about $y$ to $y\sin(xy)$, note that $y\sin(xy)$ is a product of two functions of $y$, then you should use Lebniz rule.
Oct
9
answered The double partial derivative
Oct
9
answered Some trouble with a proof on $n!/(\sqrt{n})^n \geq 1$
Oct
9
comment Using generating functions find the sum $1^3 + 2^3 + 3^3 +\dotsb+ n^3$
@Graphth: I'm sorry, I'm wrong in understand and solve the problem as claim.
Oct
8
answered How to approximate this infinite integral over $1 \leq x \leq y < \infty$
Oct
8
comment Using generating functions find the sum $1^3 + 2^3 + 3^3 +\dotsb+ n^3$
@Maesumi: Yes, there exist similar approaches work for higher powers, but seems more complex.
Oct
8
comment Using generating functions find the sum $1^3 + 2^3 + 3^3 +\dotsb+ n^3$
@user1631009: I'm sorry. Because the question is of discrete type, I don't know how to deal it using generating function. Why you persist on using generating functions to solve the problem?
Oct
8
answered Using generating functions find the sum $1^3 + 2^3 + 3^3 +\dotsb+ n^3$
Oct
7
revised Integral of sinc function multiplied by Gaussian
added 2394 characters in body
Oct
6
comment Integral of sinc function multiplied by Gaussian
@jaian: Oh, I'm so sorry! I'm so careless and made a mistake! What did you mean about "where xo!=o"?
Oct
6
answered Solving a mathematical recursion to find explicit function
Oct
6
answered Integral of sinc function multiplied by Gaussian
Oct
6
answered Does this modified harmonic series converge?