1
vote
1answer
24 views

Effect on roots of function on taking the derivative of the function

Suppose there is a function $$f(x)=(x-1)^{15}(x-2)^{20}(x-3)^{25}(x-4)^{30}$$ As we take the derivatives of the function, what will happen to the number of real roots and the number of distinct real ...
-4
votes
0answers
27 views

differentiate the given function. Simplify your answers [closed]

In Exercise 1 through 28, differentiate the given function. Simplify your answers y=√2X
3
votes
2answers
61 views

Determine the number of zeros in the first quadrant

This is a homework question: $$f(z) = z^2 - z + 1$$ sorry for the poor code!
1
vote
3answers
101 views

Prove that $f(x)=(e^x-1)(x^2+3x-2)+x$ has exactly one positive root, exactly one negative root and one root at $x=0$.

Prove that the function $f(x)=(e^x-1)(x^2+3x-2)+x$ has exactly one positive root, exactly one negative root and one root at $x=0$. My work so far: $f(0)=0$ Thus, $x=0$ is a root. For the ...
0
votes
0answers
19 views

Padé approximant of transfer function with gain and time delay.

$$ H(\omega) = A e^{-j \omega \tau} $$ I'm trying to use Padé approximation to generate a numerator and denominator polynomial for the above transfer function but genuinely struggling with how to ...
1
vote
4answers
56 views

Let $f(x)=x^2+17x+a$, $g(x)=x^2-17x-a$, $r$ a root of $f$ and $-r$ a root of $g$. Determine the roots of $f$.

Let $f(x)=x^2+17x+a$ and $g(x)=x^2-17x-a$. Suppose $r$ is a root of $f$ and $-r$ is a root of $g$. Determine all roots of $f$. From the descriptions, I can conclude that $f(x)-g(x)=2a$. But that ...
1
vote
2answers
42 views

Need help with a proof concerning zero-free holomorphic functions.

Suppose $f(z)$ is holomorphic and zero-free in a simply connected domain, and that $\exists g(z)$ for which $f(z) =$ exp$(g(z))$. The question I am answering is the following: Let $t\neq 0$ be a ...
0
votes
4answers
38 views

Finding the Zeros of A Function

In my Algebra II class we are learning how to find the zeros of a function, but I find the process very confusing despite the many efforts of my algebra teacher to explain them to me. I understand ...
18
votes
2answers
618 views

Prove that there exists $n\in\mathbb{N}$ such that $f^{(n)}$ has at least n+1 zeros on $(-1,1)$

Let $f\in C^{\infty}(\mathbb{R},\mathbb{R})$ such that $f(x)=0$ on $\mathbb{R}$\ $(-1,1)$. Prove that there exists $n\in\mathbb{N}$ such that $f^{(n)}$ has at least n+1 zeros on $(-1,1)$ My attempt : ...
2
votes
2answers
72 views

Question about bisection method

We have $f(x)=(x-1)^3(x-2)(x-3)$. $a_0<1,b_0>3$. We had to show that if $\frac{a_0+b_0}{2}\ne 1,2,3$, there is one root of $f$ that we can't get it by the bisection method. I guess that this is ...
0
votes
0answers
51 views

Demostrating that a trascendental function can be expressed as a product of its roots [duplicate]

I'm doing a work about the product of Wallis, a formula to calculate pi that is π/2= ∏ (2n/2n-1)· (2n/2n+1) from n=1 to n=∞. I have to prove the formula, and I have been searching in books and all ...
1
vote
3answers
553 views

Use the intermediate value theorem to show a function has a root [closed]

Let $f$ be a function defined on $(-\infty, 0)$ by $$f(x) = x^3 + \frac{4}{x^2} + 7 \ .$$ Use the Intermediate Value Theorem to show that the given function has at least one zero in the ...
3
votes
1answer
128 views

Finding roots of a function in an interval

Does the equation $x^3-12x+2=0$ have three solutions in the interval $[-4,4]$? We know that this is a continuous function because it's a polynomial, and so we can use the Intermediate Value ...
0
votes
0answers
30 views

Conversion of roots of a polynomial

I'm wondering, given a polynomial $P(x)$ with roots $r_i (1\le i\le n)$, how to determine the polynomial $Q(x)$ such that its roots are $r'_i=f(r_i)$. For example, if $P(x)=x^2-x-6=(x-3)(x+2)$ and ...
1
vote
1answer
45 views

At which parameter value $c>0$ do the number of solutions of $\log(1+x^2)=x^c$ change?

I'm looking at the functions $x\mapsto \log(1+x^2)$ and $x\mapsto x^c,\ c>0$ on the interval $\mathbb R^+_0$. I'm interested in the properties of $$\log(1+x^2)=x^c.$$ Graphically, for small $c$, ...
0
votes
3answers
73 views

What are the methods to find approximatly the 5th roots of an equations

By which method, can I find the nearest root of : $x^5−2x+1.1=0$ ? Thank you.
-2
votes
1answer
66 views

Any reference ,$f(x)=x e^x-2$? [closed]

$f(x)=xe^{x}-2$ $f(0)=-2$ $f(1)=e-2$ $x_{1}=x_{0}-\frac{f(x)}{f^{'}(x)}$ A better book to refer for this.
0
votes
1answer
107 views

Help with finding the roots of a function

I have the following problem: Find the smallest root of the function $e^{-x} = \sin (x)$ and focus the root with Newton's method to $8$ decimal accuracy. Any suggestions? :) Thank you for any ...
3
votes
1answer
216 views

Solve $x+y+z = x^3 + y^3 + z^3 = 8$ in $\mathbb{Z}$

Solve $x+y+z = x^3 + y^3 + z^3 = 8$ in $\mathbb{Z}$ First I tried to transform this equation, substituting $x = 8-y-z$. So I end up with: $$x^3 + y^3 + z^3 = 8$$ $$(8-y-z)^3 + y^3 + z^3 = 8$$ ...
2
votes
2answers
132 views

Prove that $f$ has finite number of roots

Let $f:[0,1]\to \mathbb{R}$ be a differentiable function. If there do not exist any $x\in[0,1]$ such that $f(x)=f'(x)=0$, prove that $f$ has only finite number of zeros in $[0,1]$. I'm not ...
3
votes
2answers
30 views

Finding a function with properties

I am looking for a function $f(x)$ with the following properties: Positive for $x\in(-\infty, 0)$ but tangent to the x-axis at $x=-1$ A root at $x=0$ and negative for $x\in(0, 2)$ A root at $x=2$ ...
22
votes
2answers
484 views

How to show that a root of the equation $x (x+1)(x+2) … (x+2009) = c $ can have multiplicity at most 2?

How to show that a root of the equation $$x (x+1)(x+2) ....... (x+2009) = c $$ can have multiplicity at most 2 , and to find the value of $ c $ for which this is possible. I proceeded by using the ...
1
vote
2answers
335 views

find number of solution for given equation

suppose we we have following equations and conditions Let $k$ be the number of real solutions of the equation $e^x+x-2=0$ in the interval $[0, 1]$ and and let $n$ be the number of real solutions ...
1
vote
1answer
40 views

Formula to scale a series that is being bent with a root / power.

I have a reference number, Rx, and a series of numbers, Sx[], to compare to it. Let's call the output Ox[]. I am using a simple square root to accelerate the apparent difference between the reference ...
3
votes
1answer
63 views

Number of roots $|f(|x|)|$ has according to $f$

If $f$ has one root on $(-\infty,0)$ and two distinct roots on $(0,+\infty)$ and $f(0)=-1$, how many roots does $|f(|x|)|$ have? I know graph of $|f(|x|)|$ should be in quadrant I because $x$ ...
0
votes
1answer
70 views

First derivative

What would be the further steps for the case like this: I am finding the first derivative of a function: $f(x) = \ln(1+x^2)$ So the procedure would then be: $f'(x) = \frac{2x}{1+x^2}$. $f'(x) ...
2
votes
2answers
374 views

Chord dividing circle , function

Two chords PA and PB divide circle into three parts. The angle PAB is a root of f(x)=0. Find f(x) Clearly , PA and PB divides circle into three parts means it divides it into 3 parts of equal areas ...
1
vote
2answers
135 views

Can the inverse of this logit-like transformation be stated analytically?

For $\alpha \geq 0$ the transformation $x \mapsto \log(x) - \alpha \log(1-x)$ maps the unit interval to the real line (in fact for $\alpha = 0$ the transformation is not surjective). For $\alpha=1$ ...