Y = nthroot(X,N) returns
the real nth root of the elements of X. Both X and N must
be real scalars or arrays of the same size. If an element in X is
negative, then the corresponding element in N must
be an odd integer.

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

X = [-2 -2 -2; 4 -3 -5]
N = [1 -1 3; 1/2 5 3]

X =
-2 -2 -2
4 -3 -5
N =
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 =
-2.0000 -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).

Input array, specified as a scalar, vector, matrix, or multidimensional
array. X can be either a scalar or an array of
the same size as N. The elements of X must
be real.

Roots to calculate, specified as a scalar or array of the same
size as X. The elements of N must
be real. If an element in X is negative, the corresponding
element in N must be an odd integer.

While power is a more efficient
function for computing the roots of numbers, in cases where both real
and complex roots exist, power returns only the
complex roots. In these cases, use nthroot to obtain
the real roots.