MATLAB: How to solve equation

MATLABsolve

equ = x^3 + (29*x^2)/100 - (1351*x)/100 + 359/50 == 0
Spectrum = solve(equ, x)
Hi, trying to solve this equation but get something like that.
Spectrum =
 
 root(z^3 + (29*z^2)/100 - (1351*z)/100 + 359/50, z, 1)
 root(z^3 + (29*z^2)/100 - (1351*z)/100 + 359/50, z, 2)
 root(z^3 + (29*z^2)/100 - (1351*z)/100 + 359/50, z, 3)

Best Answer

First
You can force MATLAB to write its explicit form using MaxDegree with solve()
syms x
equ = x^3 + (29*x^2)/100 - (1351*x)/100 + 359/50 == 0
Spectrum = solve(equ, x, 'MaxDegree', 3)
Result
Spectrum =
                                                                                                                                                                                                            406141/(90000*(- 114584939/27000000 + (1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000)^(1/3)) + ((1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000 - 114584939/27000000)^(1/3) - 29/300
 - (3^(1/2)*(406141/(90000*(- 114584939/27000000 + (1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000)^(1/3)) - ((1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000 - 114584939/27000000)^(1/3))*1i)/2 - 406141/(180000*(- 114584939/27000000 + (1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000)^(1/3)) - ((1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000 - 114584939/27000000)^(1/3)/2 - 29/300
   (3^(1/2)*(406141/(90000*(- 114584939/27000000 + (1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000)^(1/3)) - ((1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000 - 114584939/27000000)^(1/3))*1i)/2 - 406141/(180000*(- 114584939/27000000 + (1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000)^(1/3)) - ((1200000000^(1/2)*88664127737^(1/2)*1i)/1200000000 - 114584939/27000000)^(1/3)/2 - 29/300
Second
Or you can get output in variable precision numeric format
syms x
equ = x^3 + (29*x^2)/100 - (1351*x)/100 + 359/50 == 0
Spectrum = vpa(solve(equ, x, 'MaxDegree', 3))
Result
Spectrum =
  3.2163511711964122946143841774131 + 3.6734198463196484624023016788195e-40i
 - 4.056644260843024929305472877667 + 3.6734198463196484624023016788195e-40i
  0.55029308964661263469108870025384 - 7.346839692639296924804603357639e-40i
The solution has a tiny complex part, probably due to numeric errors. You can extract the real part like this
real(Spectrum)
Third
Directly convert to floating-point format using double
syms x
equ = x^3 + (29*x^2)/100 - (1351*x)/100 + 359/50 == 0
Spectrum = double(solve(equ, x, 'MaxDegree', 3))
Spectrum = real(Spectrum)
Result
Spectrum =
    3.2164
   -4.0566
    0.5503
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