undefined indicates results of mathematically undefined operations.
MuPAD® uses the special value undefined to indicate the results of operations that are not defined in mathematics.
You can use the undefined value as an input. Arithmetical operations involving undefined also return undefined. Multiplying infinities by 0 returns undefined.
For floating-point intervals, MuPAD uses the special value RD_NAN instead of undefined. If you use typeset mode, MuPAD displays RD_NAN as NaN in output regions. Multiplying infinities RD_INF and RD_NINF by 0 returns RD_NAN.
Perform the following operations with infinities. MuPAD returns the undefined value for these operations:
0*infinity, infinity - infinity, infinity/infinity
Compute the limit of the sine function at infinity. Since this limit does not exist (is not mathematically defined), MuPAD returns undefined:
limit(sin(x), x = infinity)
Multiply infinities by 0: