## 120 Reputation

11 years, 58 days

## roots...

I tried to find a root of polynomail of higer degree than that one, and i get the roots why this one not possible??

eq5:=u->-(2*(1+2*u+k*u^2))*(-2-3*k*u+k^2*u^3)*(-2*k^2*u^4-8*k*u^3-4*k*u^2+b*k*u^2-8*u^2-8*u-2-b);

sol:=(solve(eq5(u),u)): S:=array([],1..3): S[1]:=(eval(sol[1])):S[2]:=sol[2]:S[3]:=sol[3]:

r=S[1];
(1/2)
-1 + (-k + 1)
r = ------------------
k

please nedd help to find the roots of this polynomail of degree 6 withot setting values of k and b

eq5:=u->-3*b*k*u^2-3*b*k^2*u^4-k^3*u^6*b+k*u+5*k^2*u^3-b;

## thanks...

This's what i'm looking for...Many thanks

## thanks...

This's what i'm looking for...Many thanks

## I tried: eq1:=(alpha+(l+alpha)*u+alpha*...

I tried:

`eq1:=(alpha+(l+alpha)*u+alpha*k*u^2)*a=u*(alpha+(l+alpha)*u+alpha*k*u^2)*(1+l*alpha*b/((alpha+(l+alpha)*u+alpha*k*u^2))):eq2:=a=(u*(1+l*v/(1+u+k*u^2))):factor((rhs-lhs)(eq1)):eq1:=collect(%,u): factor((rhs-lhs)(eq2)): eq2:=collect(%,u):sp1:=unapply(eq1,u,a):sp2:=unapply(eq2,u,a,v):`
`a:=array(0..N1,[]):u:=array(0..N1,[]):v:=array(0..N1,[]):`
`pt1:=array(0..N1,[]): #t0:=0.0:tN:=60.0: N1:=500;th:=evalf((tN-t0)/N1):for i from 0 to N1 do u[i]:=evalf(th*i):`
`v[i]:=evalf(th*i):`
`evalf(sp1(u[i],a[i]));`
`evalf(sp2(u[i],a[i],v[i])));`
`pt1[i]:=[u[i],a[i]]:od;`

## I tried: eq1:=(alpha+(l+alpha)*u+alpha*...

I tried:

`eq1:=(alpha+(l+alpha)*u+alpha*k*u^2)*a=u*(alpha+(l+alpha)*u+alpha*k*u^2)*(1+l*alpha*b/((alpha+(l+alpha)*u+alpha*k*u^2))):eq2:=a=(u*(1+l*v/(1+u+k*u^2))):factor((rhs-lhs)(eq1)):eq1:=collect(%,u): factor((rhs-lhs)(eq2)): eq2:=collect(%,u):sp1:=unapply(eq1,u,a):sp2:=unapply(eq2,u,a,v):`
`a:=array(0..N1,[]):u:=array(0..N1,[]):v:=array(0..N1,[]):`
`pt1:=array(0..N1,[]): #t0:=0.0:tN:=60.0: N1:=500;th:=evalf((tN-t0)/N1):for i from 0 to N1 do u[i]:=evalf(th*i):`
`v[i]:=evalf(th*i):`
`evalf(sp1(u[i],a[i]));`
`evalf(sp2(u[i],a[i],v[i])));`
`pt1[i]:=[u[i],a[i]]:od;`

I was thinking in easiest way by plug these two equations in  for loop to get (a,u) from the first equation thenn (a,v) since v depend on (a,u).

Can you plz help on that.

I was thinking in easiest way by plug these two equations in  for loop to get (a,u) from the first equation thenn (a,v) since v depend on (a,u).

Can you plz help on that.

## points...

First I would like to thank u for ur quick reply.

I need some explanations plz..

First, is it possible to define an implicit eqs as:

`eq1:=(alpha+(l+alpha)*u+alpha*k*u^2)*a=u*(alpha+(l+alpha)*u+alpha*k*u^2)*(1+l*alpha*b/((alpha+(l+alpha)*u+alpha*k*u^2)));`
`and `
`eq2:=a=(u*(1+l*v/(1+u+k*u^2)));`
`when you define`
`points:=seq([a,fsolve(eval(eq1,params),u)],a=0..20); was this means that points (a,u) becuase the roots of u are one real and two complex conjugates..and i want the real one.`
`Note eq1 is F(a,u) and eq2 is g(a,u,v)`
`my goal is to plot points (a,v)`
`Thanks in advanced.`

## points...

First I would like to thank u for ur quick reply.

I need some explanations plz..

First, is it possible to define an implicit eqs as:

`eq1:=(alpha+(l+alpha)*u+alpha*k*u^2)*a=u*(alpha+(l+alpha)*u+alpha*k*u^2)*(1+l*alpha*b/((alpha+(l+alpha)*u+alpha*k*u^2)));`
`and `
`eq2:=a=(u*(1+l*v/(1+u+k*u^2)));`
`when you define`
`points:=seq([a,fsolve(eval(eq1,params),u)],a=0..20); was this means that points (a,u) becuase the roots of u are one real and two complex conjugates..and i want the real one.`
`Note eq1 is F(a,u) and eq2 is g(a,u,v)`
`my goal is to plot points (a,v)`
`Thanks in advanced.`

## ok, if the function f(B,F)=  wher...

ok,

if the function f(B,F)=

where B and F are real positive values.

N=

I need to plot the surface f as a contourplot when f=0 and f<0

## I need the output as table for the solut...

`I need the output as table for the solutions`
`i t[t] u1[i]`
`i think the best way is  to write the table with fprintf and read it in exel for exaple, but i dont know the directory format for fopen..`
`thanx`
` `

## Thaks for ur reply the question now I wa...

the question now I want to plot this output( range) multiply by f(d)

but i cant do multiply range by somthing

what shall i do?