MATLAB: Equations instead of plain values (roots)

problem value display equation

Hello, my question is: Why does Matlab show me proper values but in a form of equations?

Preview:

F =
   133/2 - (3^(1/2)*(- 4116459*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) - 130485*6^(1/2)*(532506243 + 3^(1/2)*334349677327873^(1/2)*175i)^(1/2) + 8046*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) - ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2))^(1/2))/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6)*(36207*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/3) + 9*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(2/3) + 37048131)^(1/4)) - (4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2)/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6))
   133/2 + (3^(1/2)*(- 4116459*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) - 130485*6^(1/2)*(532506243 + 3^(1/2)*334349677327873^(1/2)*175i)^(1/2) + 8046*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) - ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2))^(1/2))/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6)*(36207*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/3) + 9*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(2/3) + 37048131)^(1/4)) - (4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2)/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6))
   (4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2)/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6)) - (3^(1/2)*(- 4116459*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) + 130485*6^(1/2)*(532506243 + 3^(1/2)*334349677327873^(1/2)*175i)^(1/2) + 8046*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) - ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2))^(1/2))/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6)*(36207*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/3) + 9*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(2/3) + 37048131)^(1/4)) + 133/2
   (4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2)/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6)) + (3^(1/2)*(- 4116459*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) + 130485*6^(1/2)*(532506243 + 3^(1/2)*334349677327873^(1/2)*175i)^(1/2) + 8046*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2) - ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3)*(4023*((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(1/3) + ((3^(1/2)*334349677327873^(1/2)*525i)/2 + 1597518729/2)^(2/3) + 4116459)^(1/2))^(1/2))/(2*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/6)*(36207*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(1/3) + 9*(1597518729/2 + (3^(1/2)*334349677327873^(1/2)*525i)/2)^(2/3) + 37048131)^(1/4)) + 133/2

Why do I have to solve each equation to get a value instead of having (for example) a value of 3.7054 for the first element of the vector F? I tried to use commands from my code just in the command window and I got value in an expected form.

Here's my code:

function [ r,l,n ] = potegowa( A,eps,maxIter )
%UNTITLED5 Summary of this function goes here
%   Detailed explanation goes here
%eps=10^-6;
%A=[22,21,-8,4; 21,49,11,39; -8,11,60,-19; 4,39,-19,135];
r=0;
err=1;
[wym1 wym2]=size(A)
t=rand(wym1,1);
for n=1:maxIter
tp=t;
t=A*t;
rp=r;
r=norm(t)/norm(tp);
t=t/norm(t);
if  eps>abs(r-rp)
      break
  end 
  end
  syms lam
  B=A-lam.*eye(wym1)
  C=det(B)
  D=coeffs(C)
  E=fliplr(D)
  F=roots(E)

I'm looking forward to seeing any tips! Thanks

Best Answer

They are not ‘equations’. They are symbolic quantities. To convert them to double values, use the double function:

F = double(roots(E))

The imaginary parts are negligible in this example, so consider using:

F = real(double(roots(E)))

Related Solutions

MATLAB: Como interpreto los resultados de rootof

>> solve(y5,'MaxDegree',4)
 
ans =
 
 - ((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2)/(6*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/6)) - (- (6824144844545663996288226600305251*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2))/14167099448608935641088 + (270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3)*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2))/10737418240000 - 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3)*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2) + (11480946291063714818364437*6^(1/2)*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/2852213850513516153367582212096 + 25022842500945279188251800294332418365822272572081/162259276829213363391578010288128)^(1/2))/2415919104000000)^(1/2)/(6*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/6)*((270053049741483176957*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/3))/21474836480000 + 9*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/4)) - 33766/75
 - ((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2)/(6*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/6)) + (- (6824144844545663996288226600305251*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2))/14167099448608935641088 + (270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3)*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2))/10737418240000 - 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3)*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2) + (11480946291063714818364437*6^(1/2)*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/2852213850513516153367582212096 + 25022842500945279188251800294332418365822272572081/162259276829213363391578010288128)^(1/2))/2415919104000000)^(1/2)/(6*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/6)*((270053049741483176957*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/3))/21474836480000 + 9*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/4)) - 33766/75
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   ((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2)/(6*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/6)) + (- (6824144844545663996288226600305251*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2))/14167099448608935641088 + (270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3)*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2))/10737418240000 - 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3)*((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(1/3))/21474836480000 + 9*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184 + 8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/2) - (11480946291063714818364437*6^(1/2)*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/2852213850513516153367582212096 + 25022842500945279188251800294332418365822272572081/162259276829213363391578010288128)^(1/2))/2415919104000000)^(1/2)/(6*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/6)*((270053049741483176957*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(1/3))/21474836480000 + 9*(8340947500315093062750600098110806121940757524027/2920666982925840541048404185186304 + (2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292582270353705606829052391889249765897296843924125328233^(1/2)*1i)/154019547927729872281849439453184)^(2/3) + 6824144844545663996288226600305251/14167099448608935641088)^(1/4)) - 33766/75

RootOf(expression_in_z, z) stands for the set of values, z, such that expression_in_z comes out zero -- the roots of a polynomial. The indexing you are seeing such as [3] means the third such root out of 4 possible roots. It is not publicly documented how MATLAB sorts the roots; it mostly appears to be by absolute value first and then complex angle within the same absolute value, but this is not done consistently.

In later versions of MATLAB than yours, you would start seeing root() instead of RootOf, such as

 root(z^4 + (135064*z^3)/75 - (60454945359019375*z^2)/68719476736 + (99687985291596925*z)/1610612736 + 126533135130601452584060625/36028797018963968, z, 1)
 root(z^4 + (135064*z^3)/75 - (60454945359019375*z^2)/68719476736 + (99687985291596925*z)/1610612736 + 126533135130601452584060625/36028797018963968, z, 2)

This is the same basic functionality as RootOf(), except that it incorperates the root index as part of the expression, which can be important for differentiating between the roots.

MATLAB: Function numden() seems to return false solution! Where is the mistake

isAlways(expr2 == numExpr2/denExpr2)

returns 1 (true).

Because the expression involves a number of terms, expressing it as numerator and denominator gives an expression that looks different enough from the original expression that MATLAB has a difficult time simplifying it to 0, especially working over the complex domain in combination with the abs()

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MATLAB: Como interpreto los resultados de rootof

MATLAB: Function numden() seems to return false solution! Where is the mistake

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