Finding Entire Functions Satisfying Specific Conditions

  • Thread starter Thread starter DanniHuang
  • Start date Start date
  • Tags Tags
    Function
DanniHuang
Messages
6
Reaction score
0

Homework Statement



To find entire functions which satisfy g(\frac{1}{n}) = g(-\frac{1}{n}) = \frac{1}{n^{2}}

Homework Equations



How many functions can be found?

The Attempt at a Solution



Because the function is entire, it can be expanded in the Taylor series. But how can I work out the question?
 
Physics news on Phys.org
DanniHuang said:

Homework Statement



To find entire functions which satisfy g(\frac{1}{n}) = g(-\frac{1}{n}) = \frac{1}{n^{2}}

Homework Equations



How many functions can be found?

The Attempt at a Solution



Because the function is entire, it can be expanded in the Taylor series. But how can I work out the question?

Hint :

This condition here : g(\frac{1}{n}) = g(-\frac{1}{n})

Should look oddly familiar to : g(x) = g(-x) which is the definition of an EVEN function.

For example, consider these functions :

f(x) = x^2
f(x) = x^4
...
f(x) = x^2n

;)
 
You should be able to easily find one entire function that satisfies that. A hint might be, 'don't think too hard'.
 
Zondrina said:
Hint :

This condition here : g(\frac{1}{n}) = g(-\frac{1}{n})

Should look oddly familiar to : g(x) = g(-x) which is the definition of an EVEN function.

For example, consider these functions :

f(x) = x^2
f(x) = x^4
...
f(x) = x^2n

;)

So n can only be even numbers with the Ʃa_{n}z^{n}=\frac{1}{n^{2}}. And then?
 
DanniHuang said:
So n can only be even numbers with the Ʃa_{n}z^{n}=\frac{1}{n^{2}}. And then?

Not necessarily, consider : cos(x), cosh(x), |x|

Those are all even functions as well.
 
Last edited:
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top