Determine Which Elements of Symbolic Array Are Infinite

Usingisinf, determine which elements of this symbolic matrix are infinities:

isinf(sym([pi NaN Inf; 1 + i Inf + i NaN + i]))

ans = 2×3 logical array 0 0 1 0 1 0

Determine if Exact and Approximated Values Are Infinite

Approximate these symbolic values with the 50-digit accuracy:

V = sym([pi, 2*pi, 3*pi, 4*pi]); V_approx = vpa(V, 50);

The cotangents of the exact values are infinite:

cot(V) isinf(cot(V))

ans = [ Inf, Inf, Inf, Inf] ans = 1×4 logical array 1 1 1 1

Nevertheless, the cotangents of the approximated values are not infinite due to the round-off errors:

isinf(cot(V_approx))

ans = 1×4 logical array 0 0 0 0