Finding roots by graphing in mathematica

Question: Graph the function  g(x) = x6 - 2x2 + x - 16
a. How many real roots does the graph reveal?
b. Find the roots of g(x) in table form.

Solution:



g[x_] := x^6 - 2x^2 + x - 16
Plot[g[x],{x,-4,4}, PlotStyle-> {Hue[.7], Thickness[.004]}];

SHIFT + ENTER



Part (a):

<<Miscellaneous`RealOnly`
NSolve[g[x]==0]

SHIFT + ENTER

Nonreal::warning:
  Nonreal number encountered.

{{x -> -1.69139}, {x -> 1.64428}, {x -> Nonreal}, {x -> Nonreal}, {x -> \
Nonreal}, {x -> Nonreal}}

Hence we can comment this graph reveals 2 real roots.


Part (b):

TableForm[N[Solve[g[x]==0,x],9]]

SHIFT + ENTER

See the result yourself!!!

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