Sign of real or complex value
Find the signs of these symbolic real numbers:
[sign(sym(1/2)), sign(sym(0)), sign(sym(pi) - 4)]
ans = [ 1, 0, -1]
Find the signs of the real and complex elements
of matrix A
:
A = sym([(1/2 + i), -25; i*(i + 1), pi/6 - i*pi/2]); sign(A)
ans = [ 5^(1/2)*(1/5 + 2i/5), -1] [ 2^(1/2)*(- 1/2 + 1i/2), 5^(1/2)*18^(1/2)*(1/30 - 1i/10)]
Find the sign of this expression assuming that
the value x
is negative:
syms x assume(x < 0) sign(5*x^3)
ans = -1
For further computations, clear the assumption on x
by recreating it using
syms
:
syms x
Calling sign
for a number that
is not a symbolic object invokes the MATLAB® sign
function.