6
votes
4answers
133 views

What goes wrong in this derivative?

$$ f(x) = \frac{2}{3} x (x^2-1)^{-2/3} $$ and f'(x) is searched. So, by applying the product rule $ (uv)' = u'v + uv' $ with $ u=(x^2-1)^{-2/3} $ and $ v=\frac{2}{3} x $, so $ u'=-\frac{4}{3} x ...
2
votes
1answer
73 views

Evaluate a certain derivative

Let $\{x_1,\dots,x_n\}$ be pairwise distinct complex numbers and $\{l_1,\dots,l_n\}$ a vector of natural numbers such that $l_1+l_2+\dots+l_n=N$. Let $$ h_j(x)=\prod_{i\neq j,i=1,\dots, n} ...
0
votes
1answer
325 views

How to find the equation of a graph of a rational function from a set of points?

For example, the data points are: (1,1) (2,1/2) (3,1/3) (4,1/4) (5,1/5) How do I find the equation from those points? Do I look at the common ratio of the y-values or something?
1
vote
1answer
164 views

Perturbations of Rational Numbers

For $a_1,a_2$, $b_1,b_2$ $\in\mathbb{R}^+$, if $a_1<b_1$ , then for any perturbation $\epsilon\in \mathbb{R}^+$, $$r_1=\frac{a_1+\epsilon}{b_1+\epsilon}>\frac{a_1}{b_1} $$ and if $a_2>b_2$, ...
1
vote
1answer
183 views

Integration of rational functions..

Some rational function is giving me some trouble... \begin{aligned} \ \int \frac {x^2-9x+16}{(x-1)(x^2+6x-7)} dx \end{aligned} I simplified it like so: \begin{aligned} \ \int \frac ...