IMSUB

What it does

IMSUB(inumber1, inumber2)

IMSUB(inumber1, inumber2) subtracts its second complex argument from its first. Both arguments are required.

Try it

=IMSUB("5+2i","1+5i") returns "4-3i": subtract real coefficients and imaginary coefficients separately. Reversing the arguments returns "-4+3i".

Quirks

Operand order matters: subtraction is neither commutative nor associative. Both arguments are required. Complex text may use lowercase i or j, but two written suffixes must agree or the current wrapper gives #VALUE!. A malformed complex number gives #NUM!. The result is complex text; extracting its coordinates with IMREAL and IMAGINARY returns ordinary numbers.

How to implement

Parse the two coefficients and suffix before doing arithmetic; use the common complex formatter afterward. Retain suffix consistency, suppress a zero component and omit the coefficient one before the imaginary unit. Formatting and parsing have their own fifteen-significant-digit rules, so testing only the algebra misses observable behaviour.

Compute (a,b)-(c,d)=(a-c,b-d). The example gives 5-1=4 and 2-5=-3. Preserve operand order; subtraction is not commutative. The current implementation uses ordinary binary64 component arithmetic. Keep error propagation and traversal of range arguments consistent with the worksheet call model; flattening values without their error policy can change which result is returned.

Rust code

53 imsub "IMSUB" (2, 2) [V "inumber1", V "inumber2"] |s, a, sv| {
    let x = complex_of(s, 0, &a[0])?;
    let y = complex_of(s, 1, &a[1])?;
    complex_text(Ok(x.sub(y)), &[x, y])
}

No implementation has been published with a Handbook test suite for this function.

Version differences

The recorded environments below distinguish a reading from a same-input comparison. Counts describe captured inputs in each environment; overlapping captures and comparisons are not totals of unique worksheet calls.

The record contains no same-input comparison between these environments. Reading different inputs on different builds does not establish either a version change or cross-build agreement.

Recorded environments and comparison details.

Alternatives

COMPLEX constructs each input; IMDIV divides; IMPOWER raises one input to a real power.

Named variants

No named variants are recorded yet.