Find the real cube root of -27.

nthroot(-27, 3)

ans = -3

For comparison, also calculate (-27)^(1/3).

(-27)^(1/3)

ans = 1.5000 + 2.5981i

The result is the complex cube root of -27.

Create a vector of roots to calculate, N.

N = [5 3 -1];

Use nthroot to calculate several real roots of -8.

Y = nthroot(-8,N)

Y = 1×3

   -1.5157   -2.0000   -0.1250

The result is a vector of the same size as N.

Create a matrix of bases, X, and a matrix of nth roots, N.

X = [-2 -2 -2; 4 -3 -5]

X = 2×3

    -2    -2    -2
     4    -3    -5

N = [1 -1 3; 1/2 5 3]

N = 2×3

    1.0000   -1.0000    3.0000
    0.5000    5.0000    3.0000

Each element in X corresponds to an element in N.

Calculate the real nth roots of the elements in X.

Y = nthroot(X,N)

Y = 2×3

   -2.0000   -0.5000   -1.2599
   16.0000   -1.2457   -1.7100

Except for the signs (which are treated separately), the result is comparable to abs(X).^(1./N). By contrast, you can calculate the complex roots using X.^(1./N).